Effect of kisspeptin on in vitro maturation of sheep oocytes

Aim: The aim of this study was to investigate the effect of kisspeptin (KP) on in vitro maturation (IVM) of sheep oocytes aspirated from the ovaries collected from slaughterhouse. Materials and Methods: Two different experiments were conducted to investigate the effect of KP (5, 10 and 15 mu g/ml) alone (experiment 1) or in combination with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Estradiol (E-2) (experiment 2) on IVM of sheep oocytes. Tissue culture medium 199 supplemented with Gentamicin was used as control medium. Good quality oocytes were randomly allocated into different IVM media and cultured at 38.5 degrees in 5% CO2 under humidified atmosphere for 24 h. The oocytes were evaluated for their cumulus cell expansion (CCE) and extrusion of the 1st polar body (PB) at the end of maturation. Results: The proportion of oocytes showing CCE and extrusion of PB was highest when the oocytes were matured in the medium supplemented with 10 mu g/ml of KP. In experiment 2, oocytes were matured in 12 different maturation media (G(1)-G(12): G(1): Control, G(2): KP alone, G(3): FSH, G(4): FSH+KP, G(5): LH, G(6): LH+KP, G(7): E-2, G(8): E-2+KP, G(9): FSH+LH+E-2, G(10): FSH+LH+E-2+KP, G(11): FSH+LH+E-2+fetal bovine serum (FBS), G(12): FSH+LH+E-2+FBS+KP). The proportion of oocytes showing cumulus expansion and PB extrusion was highest (98.33 +/- 1.05 and 89.17 +/- 2.38) when they were matured in FSH+LH+E-2+FBS+KP (G(12)) and was significantly higher than other groups. The proportion of CCE and extrusion of PB was significantly increased when KP was supplemented to FSH and E-2, but no effect was observed with LH. The maturation rates were significantly increased when FSH, LH, and E-2 (G(9)) containing media were additionally supplemented with KP (G(10)). Conclusion: This study demonstrated that the addition of KP (10 mu g/ml) to the FSH, LH, and E-2 supplemented media would enhance the sheep oocyte maturation in vitro.