Ammonium detoxifying activity is maintained after 72 hours of cold preservation of rat hepatocytes in University of Wisconsin (UW) solution

The ammonium removal efficiency (ARE) and cell viability was investigated in freshly isolated rat hepatocytes exposed to increasing ammonium loads (0.1-2.0 mM). No difference was observed in both ARE and cell viability at the different ammonium concentrations tested. Storage of hepatocytes at 0 degrees C for 72 hours inhibited ammonium removal and urea synthesis. Rewarming of cells at 37 degrees C for 120 min was followed by an ARE fully comparable to freshly isolated hepatocytes. These data indicated that cold preservation of rat hepatocytes for 3 days in UW followed by a rewarming is associated with normal ammonium detoxification efficiency.     

Structural and functional changes in ultrasonicated bovine serum albumin solutions

Effects of high-intensity ultrasonication on functional and structural properties of aqueous bovine serum albumin (BSA) solutions were investigated. The functional properties of BSA were altered by ultrasonication. Surface activity of BSA increased. Minimal changes were observed in the global structure of BSA but surface charge increased particularly at basic pH values (e.g. pH>9). While dynamic light scattering measurements indicated that the particle size increased up to 3.4 times after 90 min of sonication, no significant increase in the oligomeric state of BSA using blue native PAGE was observed. The amount of free sulfhydryl groups in BSA after 90 min of sonication decreased. The increased particle size and decreased number of free sylfhydryl groups may be attributed to formation of protein aggregates. Surface hydrophobicity increased and circular dichroism spectroscopy and FTIR analysis indicated changes in the secondary structure of BSA. We hypothesize that mechanical, thermal and chemical effects of ultrasonication resulted in structural changes in BSA that altered the functional properties of the macromolecule which may be attributed to the formation of an ultrasonically induced state that differs from a thermally, mechanically or solvent induced state.     

Protein Corona Modulates Distribution and Toxicological Effects of Silver Nanoparticles In Vivo

Exploitation of silver nanoparticles (AgNPs) in biomedicine represents more than one third of their overall applications. Despite their wide use, detailed toxicokinetic data and information on their action mechanisms in vivo are still scarce. One important obstacle is their fate and transformation patterns in biological environments where AgNPs get a “new face” after interaction with biomolecules, particularly proteins. The impact of protein corona on AgNP effects in vivo is eludicated. The in vivo effects of AgNPs prepared with two different protein coronas, albumin, and metallothionein, with polymer‐coated AgNPs are compared in male and female Wistar rats after intravenous administration. The results demonstrate that the character of the protein coronas on the AgNP surface affects not only distribution, but also oxidative stress response and genotoxicity in tissues of rat exposed to AgNPs. Additionally, sex‐related effects are observed. By emphasizing the importance of protein corona formation and sex‐related response, the obtained data support a reliable evidence base needed for assessing the health risks of the steadily increasing human exposure to AgNPs.     

Short-term stromal alterations in the rat ventral prostate following alloxan-induced diabetes and the influence of insulin replacement

The stromal microenvironment is pivotal to prostate physiology and malign transformation. Diabetes leads to testosterone withdrawal and affects the prostate stromal compartment and smooth muscle cells in a similar way to that observed after castration. However the response of these cells and their involvement in extracellular matrix remodeling is not satisfactorily understood. We investigated the changes caused in the short term (one week) by alloxan-induced diabetes in the stromal components of the rat ventral prostate (VP) with an emphasis on morphological alterations of stromal cells, their conversion to a myofibroblast phenotype and the remodeling of extracellular matrix and the influence of insulin therapy. Adult male Wistar rats were assigned into untreated diabetic (n=12), insulin-treated (n=8) diabetic and control (n=10) groups. Diabetes was induced by means of the injection of alloxan (40 mg/kg b.w.), while the control animals received saline solution only. Insulin (5 UI) was administered daily for one week after diabetes diagnosis. Testosterone and estrogen plasma levels were determined. VP was analyzed using transmission electron microscopy. The main stromal cells were identified by means of light microscopy, using immunocytochemistry for specific markers - vimentin for fibroblasts, α-actin for smooth muscle cells (smc) and vimentin/calponin for myofibroblasts, following the estimation of their relative frequency and absolute volume by means of stereology. After one week diabetes led to a marked decrease in testosterone levels and an atrophy of about 35% in the VP. The relative frequency of smc and collagen fibers increased in the VP of diabetic rats but their absolute weight remained unchanged. Experimental diabetes promptly altered smc morphology which assumed at the ultrastructural level a shrunken appearance with the approximation of cytoplasmic dense bodies and also exhibited a decreased immunoreactivity to calponin. The conversion of stromal cells to a myofibroblast phenotype did not occur in alloxan-induced diabetes, as evaluated by double immunoreaction to calponin and vimentin. Insulin treatment maintained testosterone levels and preserved at least partly the cell morphology and collagen fiber organization of the prostate stroma in short-term diabetes. The apparent collagen increase observed by means of microscopic analysis in the stromal prostate compartment in the short term after diabetes is mainly associated with gland atrophy and does not involve the formation of new collagen fibers, the generation of myofibroblast-like cells or the acquisition of a secretory phenotype by stromal cells.     

Magnetic resonance imaging (MRI) and pathophysiology of the rat kidney in streptozotocin-induced diabetes.

Proton magnetic resonance imaging was performed on rats before induction of diabetes with streptozotocin (STZ) and at 2 and 12 days postinduction. Images revealed an increase in maximal longitudinal and axial dimensions of the kidneys at 2 days and a further increase at 12 days. Similarly, an increase in the size of the remaining kidney was seen in a rat which underwent uninephrectomy as a positive control. Two major differences were observed between the kidney undergoing compensatory hypertrophy and those developing diabetic nephropathy: (i) Expansion of the renal vasculature was seen only in images of the diabetic rat; (ii) A loss in conspicuity of the normal corticomedullary junction was seen in the T2-weighted images of the diabetic rat but not in the uninephrectomized rat. Histologic examination revealed that the medulla increased to a size greater than the cortex during diabetic nephropathy whereas the medullary volume was less than that of the cortex during compensatory hypertrophy. In vitro T1 relaxation times in cortex, outer medulla and inner medulla of kidneys from control rats were measured and compared with the same respective regions in diabetic rats. When these values were correlated with tissue water content, a linear increase in relaxation rate versus percent water content from cortex to inner medulla was found in the control kidneys, but this correlation was absent in diabetic nephropathy. These studies demonstrate that MRI is an effective noninvasive tool for studying the course of renal hypertrophy and hydration changes in the development of renal disease in STZ-induced diabetes in the rat.     

Interfacing biomembrane mimetic polymer surfaces with living cells - Surface modification for reliable bioartificial liver

The surface design used for reducing nonspecific biofouling is one of the most important issues for the fabrication of medical devices. We present here a newly synthesized a carbohydrate-immobilized phosphorylcholine polymer for surface modification of medical devices to control the interface with living cells. A random copolymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate (BMA), and 2-lactobionamidoethyl methacrylate (LAMA) was synthesized by conventional radical polymerization. The monomer feeding ratio in the copolymer was adjusted to 24/75/1 (MPC/BMA/LAMA). The copolymer (PMBL1.0) could be coated by solvent evaporation from an ethanol solution.Cells of the human hepatocellular liver carcinoma cell line (HepG2) having asialoglycoprotein receptors (ASGPRs) were seeded on PMBL1.0 or poly(BMA) (PBMA)-coated PET plates. On PBMA, many adherent cells were observed and were well spread with monolayer adhesion. HepG2 adhesion was observed on PMBL1.0 because the cell has ASGPRs. Furthermore, some of the cells adhering to PMBL1.0 had a spheroid formation and similarly shaped spheroids were scattered on the surface. According to confocal laser microscopic observation after 96 h cultivation, it was found that albumin production preferentially occurred in the center of the spheroid. The albumin production of the cells that adhered to PBMA was sparse. The amount of albumin production per unit cell that adhered to PMBL1.0 was determined by ELISA and was significantly higher than that which adhered to PBMA.Long-term cultivation of HepG2 was also performed using hollow fiber mini-modules coated with PMBL1.0. The concentration of albumin produced from HepG2 increased continuously for one month. In the mini-module, the function of HepG2 was effectively preserved for that period. On the hollow fiber membrane, spheroid formation of HepG2 cells was also observed.In conclusion, PMBL1.0 can provide a suitable surface for the cultivation of hepatocytes and has great potential for producing reliable bioartificial liver (BAL) devices.     

Peliosis hepatis and neoplastic/dysplastic lesions in aged male Long-Evans Cinnamon rats: MR imaging with pathologic correlation

The Long-Evans Cinnamon (LEC) rat, an animal model of Wilson's disease, abnormally accumulates copper in the liver. There have been a lot of reports on preneoplastic and neoplastic hepatic tumors in LEC rats, but few studies have been focused on other lesions. The aim of this study was to describe the MR findings of the liver of LEC rats with pathologic correlation to characterize the hepatic lesions developed in them. We measured MR images of the liver of six aged (over the age of 70 weeks old) male LEC rats. Measurements of T(1), T(2)-weighted images, and the dynamic and delayed studies after i.v. gadolinium injection were performed. The rats were sacrificed immediately after the measurements, and the diagnosis was histologically made. We identified seven lesions of peliosis hepatis, three neoplastic/dysplastic lesions, three cysts and one cholangiofibrosis. Peliosis hepatis was characterized as showing a significantly long T(2) relaxation time of 57.9 +/- 13.3 ms (mean +/- standard deviation) compared with 41.3 +/- 1.7 ms in normal liver, and prolonged enhancement after a gadolinium injection. Neoplastic/dysplastic lesions tended to show prolonged T(2), and they showed isointensity on T(1)-weighted images. They were best characterized by early enhancement followed by a rapid wash-out after a gadolinium injection. In conclusions, the frequent occurrence of peliosis hepatis observed in the present study suggests this can be a characteristic lesion in aged LEC rats. The characteristic MR findings enable us to distinguish between peliosis hepatis and neoplastic/dysplastic lesions.     

Ellipsometry studies of albumin films on tantalum oxide and SiO2

The adsorption of (1) bovine serum albumin in acetate buffer, (2) albumin followed by glutaraldehyde crosslinking, (3) albumin followed by exposure to an albumin/glutaraldehyde solution, and (4) albumin after the surface was subjected to treatment (3), has been studied using Ta oxide/Ta chips and SiO₂/Si wafers as substrates. The films were washed, air dried and measured in air using an automatic laser ellipsometer, 6328 Å. The films formed from treatment (3) and treatment (4) have a lower refractive index and are thicker than films formed from treatment (1) and treatment (2). The adsorption of albumin on SiO₂/Si wafers seems to be slower than that on the Ta oxide/Ta surfaces.     

Delta-opioid receptor endocytosis in spinal cord after dermenkephalin activation

Background

The delta(δ)-opioid receptors belong to the G protein-coupled receptors and in vitro studies have shown that δ-opioid receptors undergo an internalization process in response to agonist stimulation. The immediate consequence is the disappearance of receptors from the plasma membrane. This adaptation process reveals the cell's capacity to desensitize after a strong agonist stimulus. This process, if it occurs in vivo, could contribute to the tolerance phenomenon observed after opiate treatment. To study the mechanisms underlying regulation of the δ-opioid receptors in vivo, the effects of an application of the drug dermenkephalin, a potent and selective agonist of the δ-opioid receptor, were analysed in the rat spinal cord.

Results

Using immunocytochemistry and electron microscopy, we observed in control rats that membrane labelling was strictly localized at the interface between two neurites. Fifteen minutes after dermenkephalin stimulation, the plasma membrane labelling was associated with invaginated areas. Thirty minutes after stimulation, labelled vesicles were found in the cytoplasm confirming the internalization process.

Conclusions

The present findings support the view that δ-opioid receptors are internalized in response to prolonged exposure to dermenkephalin in vivo and confirm the presynaptic localization of δ-opioid receptors in the dorsal horn of the rat spinal cord.     

On the structure and normal modes of hydrogenated Ti-fullerene compounds

While nephrotoxicity of cadmium is well documented, very limited information exists on renal effects of exposure to cadmium-containing nanomaterials. In this work, ??omics?? methodologies have been used to assess the action of cadmium-containing silica nanoparticles (Cd-SiNPs) in the kidney of Sprague-Dawley rats exposed intratracheally. Groups of animals received a single dose of Cd-SiNPs (1?mg/rat), CdCl₂ (400???g/rat) or 0.1?ml saline (control). Renal gene expression was evaluated 7 and 30?days post exposure by DNA microarray technology using the Agilent Whole Rat Genome Microarray 4x44K. Gene modulating effects were observed in kidney at both time periods after treatment with Cd-SiNPs. The number of differentially expressed genes being 139 and 153 at the post exposure days 7 and 30, respectively. Renal gene expression changes were also observed in the kidney of CdCl₂-treated rats with a total of 253 and 70 probes modulated at 7 and 30?days, respectively. Analysis of renal gene expression profiles at day 7 indicated in both Cd-SiNP and CdCl₂ groups downregulation of several cluster genes linked to immune function, oxidative stress, and inflammation processes. Differing from day 7, the majority of cluster gene categories modified by nanoparticles in kidney 30?days after dosing were genes implicated in cell regulation and apoptosis. Modest renal gene expression changes were observed at day 30 in rats treated with CdCl₂. These results indicate that kidney may be a susceptible target for subtle long-lasting molecular alterations produced by cadmium nanoparticles locally instilled in the lung.     

Diet variability of Mediterranean insular populations of Rattus rattus studied by stable isotope analysis

The black rat Rattus rattus is a successful colonizer that threatens native species on numerous islands. Stable isotopes of carbon and nitrogen were used to quantify the rat diet on islands off the southern French coast. Samples of rat hair and faeces and their potential food were collected on each island. The nitrogen isotopic values of invertebrates and vegetation on Riou (near Marseille) differed from the other two islands (Hyères archipelago). This was attributed to a large colony of gulls on Riou, of which rats take great advantage. A part of the observed variability was due to methodological skews: two kinds of hair gave different results and there was an effect of the season and year of sampling but inter-island differences were noticeable. In certain cases, the food source value from plants and invertebrates could supply the total food needs of rats as there was no evidence of consumption of eggs, chicks or birds.     

EPR imaging to estimate the in vivo intracerebral reducing ability of mature rats after neonatal hypoxic-ischemic brain injury

A rat model of neonatal hypoxic-ischemic encephalopathy (Rice's model) was obtained by unilateral ligation of the common carotid artery of 7-day-old rats with hypoxia (exposure to 8% oxygen). To estimate the in vivo intracerebral reducing ability of the mature rats (8 weeks old) of Rice's model, temporal electron paramagnetic resonance (EPR) imaging of the brain of a rat receiving a blood-brain barrier-permeable nitroxide radical, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, was performed. In this imaging technique, the decay rate of the EPR signal intensity in a selected region of the brain is indicative of region-specific reducing ability. The effect of neonatal treatment of an antioxidant agent, 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), after a hypoxic-ischemic insult was also tested. It was found that the reducing ability had been depleted in the contralateral hemisphere of Rice's model rats; this depletion was suppressed by administering MCI-186.     

In vivo EPR imaging by using an acyl-protected hydroxylamine to analyze intracerebral oxidative stress in rats after epileptic seizures

EPR imaging by using an acyl-protected hydroxylamine, 1-acetoxy-3-carbamoyl-2,2,5,5-tetramethylpyrrolidine (ACP), in the head of a living rat after kainic acid (KA)-induced epileptic seizures was performed. ACP is a stable non-radical compound, but is easily deprotected with intracellular esterase to yield a hydroxylamine, which is oxidized by intracellular oxidative stress to yield an EPR-detectable nitroxide radical. From in vivo image data, the average values of EPR signal intensity from the hippocampus, striatum, and cerebral cortex were computed. There was no significant difference in cortical signal intensity between the control and KA-treated rats. The signal intensities from the hippocampus and striatum for the KA-treated rats were significantly higher than those for the control. The in vitro study showed that almost the same quantity of ACP moved into all regions of the brain of the control and KA-treated rats. These findings indicate that following a KA-induced seizure, the oxidative stress in the hippocampus and striatum is enhanced, but not so in the cerebral cortex.     

Effects of ultrasound on placental transfer during the last third of gestation in the rat

The effect of ultrasound on placental transfer in the rat has been measured in vivo. At 15, 18, 21 and 22 days of gestation one uterine horn of each anaesthetized rat was exposed, after laparatomy, to ultrasound. The control horn was effectively shielded. Radio-labelled tracers were then injected into the maternal circulation via a jugular vein cannula and fetuses removed simultaneously from both experimental and control horns at times predetermined to ensure minimal backflux from fetus to mother. Samples of maternal plasma were also taken at suitable intervals. The radioactive content of fetuses and plasma were measured and a unidirectional materno-fetal clearance value (Kmf) for each fetus calculated. It was shown that in rats whose body temperature was accurately maintained at 37 degrees C, ultrasound at the level used in the present study had no effect on placental clearance. However, in rats whose body temperature was allowed to fall to 32 degrees C, a 3 min exposure to 1.1 MHz continuous wave ultrasound at 1 W cm-2 caused a significant (p less than 0.001) decrease in the placental clearance of 22Na (by 55%) and 51Cr-EDTA (by 45%) in rats at 15 days of gestation. These effects showed no dose response and were not observed in rats at any of the other stages of gestation which we investigated. However, in rats at 21 days of gestation the clearance of 45Ca2+ was significantly (p less than 0.01) reduced (by 30%) by a similar exposure to ultrasound. It is concluded that although an interesting biological effect of ultrasound at low body temperatures has been observed, it has little relevance for the normal use of ultrasound in obstetrics.     

Social defeat stress before pregnancy induces depressive-like behaviours and cognitive deficits in adult male offspring: correlation with neurobiological changes

Background

Epidemiological surveys and studies with animal models have established a relationship between maternal stress and affective disorders in their offspring. However, whether maternal depression before pregnancy influences behaviour and related neurobiological mechanisms in the offspring has not been studied.

Results

A social defeat stress (SDS) maternal rat model was established using the resident-intruder paradigm with female specific pathogen-free Wistar rats and evaluated with behavioural tests. SDS maternal rats showed a significant reduction in sucrose preference and locomotor and exploratory activities after 4 weeks of stress. In the third week of the experiment, a reduction in body weight gain was observed in SDS animals. Sucrose preference, open field, the elevated-plus maze, light–dark box, object recognition, the Morris water maze, and forced swimming tests were performed using the 2-month-old male offspring of the female SDS rats. Offspring subjected to pre-gestational SDS displayed enhanced anxiety-like behaviours, reduced exploratory behaviours, reduced sucrose preference, and atypical despair behaviours. With regard to cognition, the offspring showed significant impairments in the retention phase of the object recognition test, but no effect was observed in the acquisition phase. These animals also showed impairments in recognition memory, as the discrimination index in the Morris water maze test in this group was significantly lower for both 1 h and 24 h memory retention compared to controls. Corticosterone, adrenocorticotropic hormone, and monoamine neurotransmitters levels were determined using enzyme immunoassays or radioimmunoassays in plasma, hypothalamus, left hippocampus, and left prefrontal cortex samples from the offspring of the SDS rats. These markers of hypothalamic–pituitary–adrenal axis responsiveness and the monoaminergic system were significantly altered in pre-gestationally stressed offspring. Brain-derived neurotrophic factor (BDNF), cyclic adenosine monophosphate response element binding protein (CREB), phosphorylated CREB (pCREB), and serotonin transporter (SERT) protein levels were evaluated using western blotting with right hippocampus and right prefrontal cortex samples. Expression levels of BDNF, pCREB, and SERT in the offspring were also altered in the hippocampus and in the prefrontal cortex; however, there was no effect on CREB.

Conclusion

We conclude that SDS before pregnancy might induce depressive-like behaviours, cognitive deficits, and neurobiological alterations in the offspring.

     

Altered state of primordial follicles in neonatal and early infantile rats due to maternal hypothyroidism: Light and electron microscopy approach

Thyroid hormones (TH) are one of the key factors for normal prenatal development in mammals. Previously, we showed that subclinical maternal hypothyroidism leads to premature atresia of ovarian follicles in female rat offspring in the pre-pubertal and pubertal periods. The influence of decreased concentration of TH on primordial follicles pool formation during neonatal and early infantile period of rat pups was not investigated previously. Maternal hypothyroidism during pregnancy has irreversible negative influence on primordial follicles pool formation and population of resting oocytes in female rat offspring. The study was done on neonatal and early infantile control (n-10) and hypothyroid (n-10) female rat pups derived from control (n-6) and propylthiouracil (PTU) treated pregnant dams (n-6), respectively. Ovaries of all pups were removed and processed for light and transmission electron microscopy (TEM). Number of nests, oogonia and oocytes per nest, primordial, primary, secondary and preantral follicles were determined. Screening for overall calcium presence in ovarian tissue was done using Alizarin red staining. Morphology and volume density of nucleus, mitochondria and smooth endoplasmic reticulum (sER) in the oocytes in primordial follicles was also assessed. Caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), both markers for apoptosis, and proliferating cell nuclear antigen (PCNA) for proliferation were determined in oocytes and granulosa cells in different type of follicles. In neonatal period, ovaries of hypothyroid pups had a decreased number of oogonia, oocytes and nests, an increased number of primordial follicles and a decreased number of primary and secondary follicles, while in early infantile period, increased number of primary, secondary and preantral follicles were found. Alizarin red staining was intense in hypothyroid neonatal rats that also had the highest content of dilated sER. Number of mitochondria with altered morphology in both groups of hypothyroid pups was increased. Apoptosis markers have not shown significant difference between groups but PCNA had an increased expression in the oocytes and granulosa cells in primordial follicles of hypothyroid rats. Light and electron microscopy analysis indicate that previously detected premature ovarian follicular atresia in pre-pubertal and pubertal hypothyroid rats is preceded with premature formation of primordial follicles followed by slight changes on sER and mitochondria in examined oocytes, and increased expression of PCNA.     

The Morpho-Functional Characteristics of Cerebral and Renal Arteries After Induced Arterial Hypertension in Rats Using Magnetic Resonance Imaging

The morpho-functional reorganization of regional vascular arteries is greatly altered after the induction of arterial hypertension (AH) in experimental rats. These changes can be examined using magnetic resonance imaging methods. In our experiment, induced AH caused arteriostenosis of cerebral arteries in two strains of rats—Wistar and OXYS (p < 0.05). In addition, we studied the changes in renal arteries in the same experiment. Compensatory vasodilatation was found in the extrarenal part of arteries. Arteriostenosis was detected in the intrarenal part of arteries, which was due to cytotoxic hypostasis of renal parenchyma. We proposed a cerebral vascular index and applied this index for precise analysis of changes in the studied arteries. This index is calculated as the ratio of the diameter of cerebral arteries to the diameter of renal arteries. The degree of differences in vasoconstriction between cerebral and renal arteries was established. Our results showed a moderate degree of differences in the vasoconstriction of cerebral arteries. In addition, the degree of differences in the vasoconstriction of intrarenal arteries revealed deeper vasoconstriction. These distinctions are 28.1% (p < 0.05) and 60.9% (p < 0.05) for Wistar and OXYS rats, respectively. Arterial morphometry revealed reduced sizes of all OXYS rat arteries compared with those of Wistar rat arteries. These pathological changes were associated with excessive stiffness (rigidity) of vascular walls due to accelerated aging. The accelerated aging of OXYS rat arteries led to a decrease in their vasodilatation potential and a decrease in the blood supply of cerebral and renal arteries. Comparative morphometry of the status of all arteries in both groups after AH revealed multiple specific changes in the remodeled arteries.     

Effect of various freezing solutions on cryopreservation of mesenchymal stem cells from different animal species

The objective of this study is to compare the effects of different well defined freezing solutions with a reduced concentration of dimethylsulfoxide (DMSO) combined with polyethylene glycol (PEG) and/or trehalose on cryopreservation of mesenchymal stem cells (MSCs) from mice, rats and calves. Post-thaw cell viability, proliferation capacity and differentiation potential of MSCs from different species were assessed after cryopreservation with the conventional slow freezing method. Although the post-thaw viabilities and metabolic activities varied among the different species, satisfactory results were obtained with 5 percent (v/v) DMSO, 2 percent (w/v) PEG, 3 percent (w/v) trehalose and 2 percent (w/v) bovine serum albumin (BSA) as the freezing solution. Our results showed that mouse MSCs were more robust to cryopreservation compared with rat and bovine MSCs.     

Molecular spectroscopic insight into the binding of batatasin V isomers to human serum albumin

Fluorescence, ultraviolet-visible absorption spectroscopy, circular dichroism spectrum, and molecular docking methods were employed to study the interaction mechanisms of batatasin V and its isomer with human serum albumin. The two isomers both bond reactively to the hydrophobic activity in subdomain IIA, with an approximate binding affinity. Thermodynamic parameters and molecular modeling results manifested that hydrogen bonds and van der Waals force were the main contributors to the interaction. The secondary structure of human serum albumin was altered with the obvious decreased amount of α-helix. The results overall suggested similar binding mechanisms of batatasin V isomers with human serum albumin. This work will promote the further study of batatasins for pharmacological function. It could also help to provide some useful information for further drug design based on batatasins.     

Molecular imaging of enhanced Na expression in the liver of total sleep deprived rats by TOF-SIMS

Sleep disorder is associated with metabolic disturbances, which was related to oxidative stress and subsequently sodium overload. Since liver plays important roles in metabolic regulation, present study is aimed to determine whether hepatic sodium, together with oxidative stress, would significantly alter after total sleep deprivation (TSD). Sodium ion was investigated by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Parameter for oxidative stress was examined by heat shock protein-25 (HSP-25) immunohistochemistry. TOF-SIMS spectrum indicated that hepatic Na⁺/K⁺ ratio counting as 82.41 ± 9.5 was obtained in normal rats. Sodium ions were distributed in hepatocytes with several aggregations. However, following TSD, the intensity for Na⁺/K⁺ ratio was relatively increased (101.94 ± 6.9) and signals for sodium image were strongly expressed throughout hepatocytes without spatial localization. Quantitative analysis revealed that HSP-25 staining intensity is 1.78 ± 0.27 in TSD rats, which was significantly higher than that of normal ones (0.68 ± 0.15). HSP-25 augmentation suggests that hepatocytes suffer from oxidative stress following TSD. Concerning oxidative stress induced sodium overload would impair metabolic function; enhanced hepatic sodium expression after TSD may be a major cause of TSD relevant metabolic diseases.