The Study of Histomorphometry and Histochemistry of Liver in Adult Male and Female Rats Following Short-term and Long-term Administration of Methylphenidate

Methylphenidate is one of the most common medications used for treatment of attention-deficit/hyperactivity disorder (ADHD). The administration of methylphenidate, through blocking of dopamine receptors and increment of extracellular dopamine levels, leads to escalation in central nervous system activity. Numerous studies investigated the effect of methylphenidate on body organs however; there is no comparative and time dependent study about the effects of this agent on the liver tissue in male and female rats. Adult male and female rats were treated with methylphenidate (10 mg/kg) for two and eight weeks. The blood level of hepatic enzymes (AST, ALT, ALP) was assessed and the liver tissue samples were prepared for morphometric studies. Microscopic studies were made by digital camera. Histochemical studies were done with Oil Red O staining method. Blood levels of hepatic enzymes were increased (especially in females) in MPH treated groups compared to control rats. Histomorphometric results revealed that the evaluated indices were reduced by following the administration of methylphenidate in male and female rats compared to control group. These reductions were noticeable in long term administration and in female rats. In histochemical investigations, there were no significant differences observed between experimental groups. The results of this study showed that, long term administration of methylphenidate could induce some alterations in hepatic enzymes and microscopic structure of the liver of rats and in this way it seems that female rats were more susceptible in comparison to male rats which can be a reflection of the greater impact of females from the side effects of methylphenidate.