Temperature induced alterations in the liver of wall lizard (Hemidactylus frenatus): morphological and biochemical parameters

Wall lizards (Hemidactylus frenatus) were adapted to 20, 25, and 30 °C, and the liver was examined using standard transmission electron microscopy (TEM) and biochemical analysis. Peroxisomes were visualized after using the 3,3′-diaminobenzidine (DAB) technique. Catalase, uricase and protein content wsere determined biochemically. The hepatocytes of animals adapted to higher temperature displayed larger lipid inclusions than those of animals adapted to lower temperature. Rough endoplasmic reticulum was better developed in the animals kept at low temperature (20 and 25 °C) than in the animals held at 30 °C. Cytoplasmic crystalline structures were visualized, and better developed in the hepatocytes at 25 °C. Peroxisomes varied with the temperature, being more frequent in the animals kept at 20 °C, while the bigger ones prevailed in the animals kept at 30 °C. The higher catalase activity at higher temperature was correlated to an increase in staining intensity of DAB-incubated peroxisomes as visualized cytochemically in TEM. The biochemical results confirmed the cytochemical reaction observed by TEM. The hepatocytes of the animals at 30 °C showed a reduction in the number of peroxisomes, however, at this temperature the largest peroxisomes with a stronger reaction to DAB and a higher activity of catalase predominate. In contrast, the uricase activity showed no significant variation in relation to adaptation temperature. Overall, these data show the morphological and functional plasticity of hepatocytes to temperature adaptation of H. frenatus.