The effect of chronic administration of methylphenidate on morphometric parameters of testes and fertility in male mice.

Background: Due to common use of methylphenidate (MPH) for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) and the role of the reproductive system in the production of gametes, studying the effects of this medication on the morphometry of testes, serum testosterone concentration, leydig cells function, and fertility rate was the aim of this study.

Methods: Twenty seven male mice (Balb/C), eight weeks old, were randomly divided into one control and two treated groups. After weighing the mice, the treated groups received MPH (produced in Novartis company) at the doses of 2 mg/kg and 10 mg/kg for 40 days. The control group received only normal saline. Subsequently, after weighing the animals, the weights of testes, dimensions of the testis, and the serum testosterone concentration were measured in six mice belonging to each group. After tissue processing, the samples were stained with hematoxylin and eosin, then the leydig cells were counted. In order to assess male fertility in each group, 3 male mice were chosen and each of them was kept with three female mice in a separate cage. After 10 days, the fertility rates of the male mice were determined by counting the number of embryos in uterus and the corpora lutea in their ovaries.

Results: The results of this study revealed that prescription of different doses of MPH can cause a significant decrease of the body weight. It reduces the number of leydig cells, too (p<0.01). Moreover, serum testosterone concentration (67.72±8.24 ng/ml in control group and 0.302±0.416 ng/ml after treatment with 2 mg/kg/day MPH) and fertility rate (95.42%±4.68% in control group and 64.96%±18.51% after treatment with 2 mg/kg/day MPH) of the male mice declined significantly in the treated groups compared with the control group (p<0.01), but it did not cause any changes in the weight or morphometric parameters of testes.

Conclusion: The results of this study confirmed that MPH can negatively affect serum testosterone concentration and fertility rate of the male mice by decreasing the number of leydig cells and reducing the body weight.