Kisspeptin is a potent stimulator of the hypothalamic- pituitary-gonadal axis and may play a critical role in modulating of stress-induced suppression of reproduction. The aim of the present study was to investigate the effect of glucocorticoid receptor antagonist (RU486) and stress on expression of Kiss-1 mRNA in arcuate nucleus (ARC) of rat hypothalamus.
Materials and methods
Twenty four male rats of the Sprague-Dawley strain were randomly allocated into stress, RU-486, stress/RU-486, and control groups (n=6). The stress group rats were immobilized 1 h/day, for 12 days through wrapping of their upper and lower limbs by packing tape with holes for ventilation. RU-486 (2.5 mg/kg, subcutaneously) for 12 days was injected into the RU-486 group rats. The stress/ RU-486 group rats were injected with the same dose of RU- 486 1 hours before the stress process for 12 days. The control group was allowed to freely move in the cages without receiving any stress or drug. All rats were decapitated and their ARC was collected. Moreover, five rats were ethically killed 2 weeks after castration and served as real time PCR control group. Relative expression of Kiss-1 mRNAs (compared to the castrated group) in ARC was determined using qualitative real-time PCR. Mean of data in four groups were compared by one-way ANOVA and LSD post-hoc test (SPSS 22; P<0.05).
Mean and SE of relative expression of Kiss-1 mRNA in ARC in the stress, RU-486, and stress/RU-486 groups (8.9 ± 2.5, 7.7 ± 1.5 and 7.9 ± 2.3%, respectively) were less than that of the control rats (27.9 ± 9.1%, P<0.05). Relative expression of Kiss-1 mRNA was not different between the stress, RU-486, and stress/RU-486 groups (P>0.05).
Chronic 12 days stress decreased Kiss-1 mRNA expression in the ARC nucleus of male rats. Therefore, decrease of male fertility by the chronic stress can be caused via the decrease of Kiss-1 mRNA expression.