Effects of methotrexate on serum testosterone level in sleep deprived male Wistar rats

Sleep deprivation has been reported to decrease testosterone levels but the mechanism remains unclear. Studies have shown that sleep deprivation increases interleukin 1 beta (IL-1β), a pro-inflammatory cytokine and that increased IL-1β levels cause reductions in Leydig cell production of testosterone. This study was therefore designed to determine the effects of methotrexate, an IL-1β blocker on serum testosterone levels in sleep deprived male Wistar rats.

Twenty male Wistar rats were randomly assigned into four groups (n = 5); group I (Control) received the vehicle (1% tween 80 solution); group II (methotrexate) received 0.5 mg/kg body weight methotrexate; group III (SD) was sleep deprived and received the vehicle; group IV (SD+Methotrexate) was sleep deprived and received 0.5 mg/kg body weight methotrexate. Sleep deprivation was induced using the modified multiple platform technique for 14 days. Treatments were administered twice weekly by oral gavage for 14 days. Blood was collected on day 14 and serum was obtained for analyses of testosterone, LH and FSH levels. IL-1β level and histology of the testis were also determined. Data were expressed as Mean ± SEM and analysed using ANOVA. p < 0.05 was considered significant.

Serum testosterone levels were significantly decreased while testicular IL-1β was increased in SD and SD+Methotrexate compared with Control. FSH and LH levels were not significantly different among the groups.

Results of this study suggest that reduction in serum testosterone level in sleep deprived rats is not dependent on increased level of IL-1β.