Relative expression profile of Kisspeptin (Kiss1-Kiss1r) and gonadotrophin receptor in the ovarian follicular tissue and their association in the Buffalo (Bubalus bubalis)

Abstract

In the past decade, kisspeptin research was primarily focussed on the regulation of GnRH release in hypothalamus. Present study was designed to explore the expression of extra-hypothalamic kisspeptinergic (Kiss1- Kiss1r) system in the follicular compartment of buffalo ovary. Buffalo genitalia (n=32) were collected immediately after exsanguinations and categorized into early luteal (EL), mid luteal (ML), follicular (FL) and acyclic (n=8 per group), based on the gross ovarian morphology. Ovarian follicular tissue samples were subjected to total RNA extraction, cDNA synthesis and qPCR amplification of Kiss1, Kiss1r, follicle stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) along with an endogenous control (β-actin) gene. The expression of ovarian Kiss1 transcripts was abundant in the cyclic than acyclic stage. The fold change was significantly upregulated in ML (66.79 fold) followed by EL (28.64 fold) and FL (14.09 fold) stages against the acyclic stage (calibrator). Similarly, the Kiss1r expression was highest at ML (77.26 fold). The expression of FSHR was upregulated at FL (15.08 fold) stage in response to follicular activity and subsequently observed to be down regulated at EL (0.09 times) and ML (0.27  times). Further, the expression of Kiss1 was positively correlated with FSHR only at ML and FL. From this study, it could be concluded that Kiss1 and Kiss1r are expressed in the buffalo ovarian follicle and their expression is associated with the stage of estrous cycle.