Previous studies have shown that kisspeptin (Kp-10) is expressed in mammalian ovaries; however, the expression and role of Kp-10 in bovine ovarian granulosa cells are still unclear. In this study, we assessed the expression of Kp-10 and its effects on the proliferation and apoptosis of bovine granulosa cells. Immunohistochemical analysis showed that Kp-10 was expressed in the cytoplasm of bovine ovarian granulosa cells. Moreover, MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2- H-tetrazolium bromide) assays showed that 100 nM Kp-10 significantly inhibited the viability of granulosa cells (P<0.01). Flow cytometry analysis showed that Kp-10 could significantly increase accumulation of cells in the G1 phase, decrease accumulation of cells in the S phase, and promote apoptosis in bovine granulosa cells (P<0.05). Additionally, Kp-10 decreased the mRNA levels of Bcl-2, an anti-apoptotic gene; increased the mRNA levels of caspase-3, a pro-apoptotic gene; and increased the mRNA levels of Fas and Fasl, two membrane surface molecule genes (P<0.05). Thus, our findings demonstrated for the first time that Kp-10 inhibited proliferation and promoted apoptosis in bovine ovarian granulosa cells. These findings provide insights into our understanding of the role of Kp-10 in mediating the proliferation of bovine granulosa cells.

• Hongyu Liu(College of Animal Science and Technology, Jilin Agricultural University, Division of Applied Life Science (BK21 Plus))
• Myeong-Don Joo(Division of Applied Life Science (BK21 Plus))
• Ji-Yoon Hwang(Division of Applied Life Science (BK21 Plus))
• Ayman Mesalam(Division of Applied Life Science (BK21 Plus), Institute of Agriculture and Life Science, Gyeongsang National University)
• Jun Wang(College of Animal Science and Technology, Jilin Agricultural University)
• Wenfa Lu(College of Animal Science and Technology, Jilin Agricultural University)
• Il-Keun Kong(Division of Applied Life Science (BK21 Plus), Institute of Agriculture and Life Science, Gyeongsang National University)