Lateral ventricle injection of orexin-A ameliorates central precocious puberty in rat via inhibiting the expression of MEG3.

BACKGROUND Central precocious puberty (CPP) is characterized as increasing gonadotropin-releasing hormone (GnRH) release. Orexin-A has also been shown to affect GnRH release. However, there are few reports about the effect of orexin A on the treatment of CPP. METHODS After establishing the precocious puberty model, the rats were divided into four groups: normal control, precocious puberty rats, precocious puberty rats treated with normal saline and precocious puberty rats treated with orexin-A. The vaginal opening time, second estrus cycle, ovarian index and uterus index of rats in each group were detected. qRT-PCR was performed to examine the expression of MEG3 and kisspeptin in rats. HT22 cells were transfected with pcDNA-MEG3 to detect the expression of Kisspeptin. RESULTS In this study, we found that orexin-A not only delayed the day of vaginal opening and regular estrus cycle days but also decreased the ovarian index and uterus index in rats with CPP. In addition, orexin-A reversed the up-regulation of MEG3 and kisspeptin in rats with CPP. In HT22 cells, the mRNA and protein level of kisspeptin were enhanced by pcDNA-MEG3. CONCLUSION Our results suggest that orexin-A ameliorates central precocious puberty in rat and MEG3 might be involved in this effect, suggesting that MEG3 might be a novel target in treating central precocious puberty.