The possible ameliorating effect of vitamin E on hyperthyroidism-induced hepatotoxicity in adult rats

Abstract

Introduction Thyroid dysfunctions are frequently associated with abnormalities of liver tests and in severe forms with histologically hepatocellular damage. Aim of the work: This study was set to evaluate the ameliorating effect of vitamin E on the hyperthyroidism inducedhepatotoxicity. Materials and methods 36 male albino rats were used in this study and divided into four equal groups: Group I:control group Group II: rats received 100 mg vitamin E dissolved in oil, via gastric tube, for 30 days. Group III: rats were received l-thyroxin dissolved in distilled water daily at a dose of 100 µg/kg body weight, via an intragastric tube for 30 days. Group IV: rats received both l-thyroxin as group III plus vitamin E as in group II for 30 days. At the end of the experiment, blood samples were obtained for assessment of some biochemical parameters. Liver specimens were obtained and processed for light and electron microscopic study. Moreover, morphometric analysis of the portal veins, blood sinusoids and bile ducts diameter was done. Results A statistically significant elevation in the levels of T3 as well as, significant elevation of ALT and AST, a significant increase in the diameter of portal veins, blood sinusoids and bile ducts was observed in the group III. Stained sections of the liver of group III showed the majority of hepatocytes were vacuolated with dark nuclei and pale vacuolated cytoplasm. Mononuclear cellular infiltrate was observed around the dilated congested portal vessels and the congested central veins. Ultrastructural study of hepatocytes revealed degenerated mitochondria, dilated rER, sER and multiple lysosomes, depletion of glycogen granules. Furthermore, there was significant improvement of the biochemical and histological pictures toward the normal among the group IV. Conclusion Hyperthyroidism is toxic to the rat hepatocytes by oxidative stress. Therefore, addition of vitamin E to the hyperthyroid patients may be recommended.