Methotrexate (MTX) is commonly used as a chemotherapy agent and immune system suppressant but its adverse effect on male reproductive system is still limited. This study aimed to investigate the effect of MTX on structure and functional proteins of testis and seminal vesicle. Adult male rats were divided into control and MTX groups (n =12). In 30 experimental days, the treated animals were injected with MTX (tail i.v., 75 mg/KgBW) at days 8 and 15. Then, the reproductive parameters and histology of both groups were examined. Thickness of seminal seminal vesicle epithelia was analyzed. Also, the expressions of testicular tyrosine phosphorylated proteins and steroidogenic acute regulatory (StAR) protein were investigated. The results showed that MTX could significantly decrease epididymal sperm concentration. In addition, the germ cell degeneration, increased spaces of interstitial tissues, and low epididymal sperm mass density were observed in MTX group. The thickness of seminal vesicle epithelia in MTX group was significantly lower than that of control group. Moreover, the intensity of testicular phosphorylated proteins of 31, 32, 72, and 85 kDas was significantly increased while of 42 and 47 kDas in MTX group was decreased as compared to control. The expression of testicular StAR protein in MTX group was also significantly decreased as compared to the control. In conclusion, MTX affects testicular and seminal tissues and changes testicular functional proteins in adult rats.
KEY WORDS: Methotrexate; Phosphorylated proteins; Testis; Seminal vesicle; Male rat.