RESUMO
This study was conducted on 140 adult male albino rats who were divided into seven equal groups, each comprised 20 rats. The first group was the negative control group, the second and the third groups were positive control rats injected with saline and received biotin orally, respectively, the fourth and fifth groups were injected with methotrexate and the sixth and seventh groups were injected with methotrexate after biotin administration. At the end of the experimental period, the rats were sacrificed, blood was collected and the liver profile [serum hepatic transaminases, alkaline phosphatase, total serum proteins and serum albumin] was investigated and liver was exposed to histological and ultrastructural examination. The results showed a remarkable deterioration in the liver biochemical parameters as well as changes in its histological and ultrastructural appearance following methotrexate administration. The changes were more pronounced in rats received the drug treatment for a longer period. In addition, biotin had improved the liver function tests and decreased the histological and ultrastructural changes caused by methotrexate. The correlation between the functional and structural changes was discussed