不同方法处理的角膜脱细胞基质组织学生物特性的比较

目的:比较不同的角膜脱细胞基质方法,旨在选择最适合的脱细胞基质方法,制备成为组织工程角膜支架材料和角膜替代物的脱细胞基质.方法:分别用胰酶-曲拉通法、SDS-戊二醛法、胰酶-冷冻法等方法对角膜进行脱细胞处理,并对脱细胞彻底的基质进行力学特性、透光率的分析.结果:用胰酶-冷冻法获得的兔角膜全层和分层基质脱细胞最彻底,基质的结构未见明显破坏,脱细胞基质在生物力学特性上与正常角膜接近,透光率低于新鲜角膜.结论:用胰酶-冷冻法获得的脱细胞基质与自然角膜接近,可作为组织工程角膜支架材料和角膜替代物.     

Development of cataract and corneal opacity in mice due to radon exposure

This work investigates the radiation damage on the eye of albino mice exposed to effective radon doses ranging from 20.92 to 83.68 mSv. These doses were taken over 2–8 weeks using a radon chamber constructed by the National Institute for Standard (Egypt). The guidance on the quality assurance program for radon measurements was followed. Therefore, the estimated doses received by the laboratory animals meet the requirements of national standard. The refractive index(RI) and protein concentration were measured for soluble proteins of both corneas and lenses. In addition, the sodium dodecyle sulfate polyacrylamide gel electrophoresis (SDSPAGE) technique was used. The results show increasing of the RI of both cornea and lens proteins and decreasing in total protein concentration of exposed animals. These results were accompanied with changes in the SDSPAGE profile for both cornea and lens. Therefore, radon exposure produces substantial hazards to the cornea and lens of experimental animals and has a crucial role in the development of cataract and corneal opacity.     

A nonlinear macroscopic multi-phasic model for describing interactions between solid,fluid and ionic species in biological tissue materials

A nonlinear, macroscopic multi-phasic model for describing the interactions between solid, fluid, and ionic species in porous materials is presented. Governing equations are derived based on the nonlinear theories of solid mechanics, linear flow theory of Newtonian fluids, and theory of irreversible thermodynamics for the transport of ions and ionic solutions. The model shows that the transport coupling between ions and ionic solution exists only when the porous material has a membrane-like feature, which could be inside the material or on the material boundaries. Otherwise, the coupling occurs only between the solid and fluid phases and the transport of ionic species will have no effect on the macroscopic stresses, strains and displacements of the porous material. As an application of the present multi-phasic model, a numerical example of the human cornea under the shock of NaCl hypertonic solution applied to its endothelial surface is presented. This is a typical example of how ionic transport induces swelling in biological tissues. The results obtained from the present multi-phasic model demonstrate that the mechanical properties of the tissue have an important influence on the swelling of the cornea. Without taking into account this influence, the predicted swelling may be exaggerated.     

Reducible Polyethylenimine Nanoparticles for Efficient siRNA Delivery in Corneal Neovascularization Therapy

The aim of this study is to establish the safe and effective ocular delivery system of therapeutic small interfering RNA (siRNA) in corneal neovascularization therapy. The major hurdle present in siRNA‐based corneal neovascularization (CNV) therapy is severe cytotoxicity caused by repetitive drug treatment. A reducible branched polyethylenimine (rBPEI)‐based nanoparticle (NP) system is utilized as a new siRNA carrier as a hope for CNV therapy. The thiolated BPEI is readily self‐crosslinked in mild conditions to make high molecular weight rBPEI thus allowing the creation of stable siRNA/rBPEI nanoparticles (siRNA‐rBPEI‐NPs). In the therapeutic region, the rBPEI polymeric matrix is effectively degraded into nontoxic LMW BPEI inside the reductive cytosol causing the rapid release of the encapsulated siRNA into the cytosol to carry out its function. The fluorescent‐labeled siRNA‐rBPEI‐NPs can release siRNA into the entire corneal region after subconjuctival injection into the eye of Sprague Dawley rats thus confirming the proof of concept of this system.

     

端粒酶转染防治角膜内皮失代偿的研究

目的评价端粒酶转染对角膜内皮细胞形态和功能的影响。方法将体外培养的猫角膜内皮细胞随机分为3组,兔端粒酶基因转染组、正常对照组和表皮生长因子组。培养30代后观察传代细胞形态和细胞周期各时相细胞比例的变化,检测端粒酶逆转录酶蛋白和Ⅳ型胶原的表达。结果兔端粒酶基因转染组细胞数目较正常对照组和表皮生长因子组增多,伸展贴壁能力增强,表型正常,G2～M期和S期细胞比例显著增加,端粒酶逆转录酶蛋白和Ⅳ型胶原的表达也较正常对照组增多。结论兔端粒酶转染可以促进猫角膜内皮细胞增殖且表型正常,可以增强其伸展粘附能力和分泌功能,有利于防治角膜内皮失代偿。     

人角膜内皮细胞株的建立与组织工程人角膜内皮的体外重建

为了体外重建出可用于角膜移植的组织工程人角膜内皮(TE-HCE),本文从业已建立的非转染人角膜内皮(HCE)细胞系中筛选出单克隆细胞株(mcHCE),并以其为种子细胞对TE-HCE的体外重建进行了研究。经有限稀释法从非转染HCE细胞系筛选出了mcHCE细胞株,形态结构、染色体分析以及细胞连接蛋白和膜运输蛋白的检测结果显示,mcHCE2401单克隆细胞株细胞具有正常而稳定的形态、结构和二倍染色体核型,并能表达细胞连接蛋白和膜运输蛋白,具有TE-HCE种子细胞的理想特征。以mcHCE2401细胞为种子细胞、以去上皮层修饰羊膜(mdAM)为载体支架体外重建出了TE-HCE,形态结构鉴定结果显示,多角形mcHCE2401种子细胞在mdAM 上形成了连续、完整的细胞单层,在细胞之间以及细胞与mdAM之间均形成了广泛的细胞连接,单层细胞密度高达3602.22±45.22个／mm²(相当于0～3岁孩童HCE的细胞密度),所重建单层角膜内皮的形态结构与在体HCE高度近似。可见,本文成功建立了形态结构、核型以及功能蛋白表达正常的单克隆细胞株,并利用mcHCE2401细胞和mdAM在体外成功重建出了形态结构与与在体HCE高度近似的最“年轻”的TE-HCE,有望作为捐献角膜内皮的等效替代物用于角膜内皮异常疾病的临床治疗。     

Invariance Conditions for Random Curvature Models

A class of probability models is introduced with the objective of representing certain properties of the geometric optics of the human eye. Astigmatic probability laws are those in which the extreme curvature values in the anterior corneal surface, measured at circularly arranged and equally spaced locations, are displaced by an approximate 90 deg angular separation. The relationship between the symmetry invariance of these probability laws for curvature data and probability laws for the ranking permutations associated with the ordering of these data is obtained. A distinction is made between the condition in which the components of the curvature ensemble are represented as real numbers from that in which these curvatures are color-coded and take value on a finite totally ordered set. A constructive principle for astigmatic laws is outlined based on algebraic arguments for the analysis of structured data.     

Corneal topography measurement by means of radial shearing interference: Part III – measurement errors

This work contains results of computer simulation researches, which define requirements for measurement conditions, which should be fulfilled so that measurement results ensure allowable errors. They define: allowable measurement errors (interferogram's scanning) and conditions, which should fulfill computer programs, so that errors introduced by mathematical operations and computer are the smallest.     

抗CD25单克隆抗体对大鼠角膜移植排斥反应的抑制作用

为了观察抗ＣＤ２５单克隆抗体（ＡＲＴ－１８）对角膜移植排斥反应的抑制作用，应用ＳＤ大鼠对Ｌｅｗｉｓ大鼠进行穿透性角膜移植、术后用抗ＣＤ２５ＭｃＡｂ治疗。结果显示：对照组大鼠角膜排斥反应发生率为１００％；ＡＲＴ－１８治疗组角膜排斥反应发生率为５３．３％；ＡＲＴ－１８联合环孢霉素Ａ治疗组角膜排斥反应发生率为２６．７％。结果表明：抗ＣＤ２５ＭｃＡｂ联合环孢霉素Ａ治疗效果更好。