Effects Of Gnih On Proliferation Of Porcine Ovarian Granulosa Cells And Activation Of Mapks Signaling Pathway

Gonadotropin-inhibitory hormone(GnIH)is a novel neuropeptide firstly found in the quail brain,which can act as an inhibitor to inhibit the synthesis and release of gonadotropins if being mediated by its receptor.Mammalian reproductive function is regulated by the hypothalamic-pituitary-gonadal axis,and many studies have shown that GnIH is involved in the reproductive regulation of animals,especially can play an important direct regulatory role in ovarian tissue by binding to its receptors,including the regulation of follicular cell proliferation,apoptosis and hormones secretion.In this study,porcine ovarian granulosa cells(pGCs)were cultured in vitro to detect the effect of different concentrations of GnIH on its proliferation and activation of MAPKs signaling pathway,and to provide experimental reference and theoretical basis for further study of GnIH regulation of pGCs.Three experiments was carried out in the present study:1)PGCs were in vitro cultured in the gradient concentrations(0,10"6,10-8,10-10 and 10-12 mol/L)of GnIH under normal conditions.The activity of pGCs in each group was detected by CCK-8.2)The effects of GnIH on the expression of CyclinD1,CyclinA2,CyclinB1,CDK1,CDK2 and CDK4 mRNA in pGCs were evaluated by semi-quantitative RT-PCR.3)The effect of GnIH on the activation of MAPKs was examined by Western blot detection of ERK1/2,P38,JNK and their phosphorylation.The results showed that 1)GnIH down-regulated the cell viability of pGCs.2)The expression of CyclinD1 and CDK1 was remarkably(P<0.01)inhibited by GnIH at different concentrations.Compared with the control,GnIH(10-6 mol/L and 10-8 mol/L)remarkably(P<0.01)inhibited the expression of CydinA2,CyclinB1,CDK2 and CDK4.3)The expression of total ERK1/2 was significantly(P<0.05)or remarkably(P<0.01)decreased in all concentrations of GnIH,and the expression of total p38 and total SAPK/JNK was significantly(P<0.05)inhibited at 10-12 mol/L.GnIH had significant inhibitory effect on p-p38 and p-ERK1/2 at low concentration(10-10 mol/L and 10-12 mol/L),and significantly inhibited p-SAPK/JNK at(10-6 mol/L and 10-10 mol/L)(P<0.05).In summary,GnIH is involved in the regulation of cell cycle of sow GCs and may inhibit the activation of MAPKs signaling pathway-associated proteins.