P-21: RF-Amide Related Peptide mRNA Expression in Male Rat Dorsomedial Hypothalamic Nucleus during Chronic Stress
Chronic stress induces male reproductive dysfunction; however, the involved mechanisms are not clear. It has been suggested that the gonadotrophin-inhibitory hormone, known as RF-amide related peptide (RFRP) in mammalian species, may mediate this inhibitory effect of stress. The objective of the present study was to compare the effect of chronic stress and glucocorticoids receptor antagonist (RU486) on expression of RFRP mRNA in dorsomedial hypothalamic nucleus (DMH) of rats.
Materials and methods
Twenty four male rats of the Sprague-Dawley strain were randomly allotted into four equal groups (n=6); stress, RU-486, stress/RU-486, and control groups. In stress group, the rats were immobilized, 1 h/day, for 12 days. In RU-486 group, the rats were injected subcutaneously with RU-486 (2.5 mg/kg) for 12 days. In stress/RU-486 group, the rats were injected subcutaneously 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 and did not receive any stress or drug. DMH of all rats were collected after 12 days. Moreover, five rats were ethically killed 2 weeks after castration and served as real time PCR control group. Relative expression of RFRP mRNAs (compared to the castrated group) in DMH was determined using 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 RFRP mRNA in DMH in the chronic stress group (106.2 ± 24.1%) was higher than that of the RU-486 and control rats (57.8 ± 3.9% and 43.6 ± 10.5%, respectively; P<0.05). Relative expression of RFRP mRNA was not different between the stress group (106.2 ± 24.1%) and stress/RU-486 rats (83.8 ± 13.9%, P>0.05).
Chronic stress (12 days) increased RFRP-3 mRNA expression in DMH of male rat which may one of pathways of fertility dysfunction in males.