Role Of NF-?B Pathway In The Transition Of Mouse Secondary Follicles To Antral Follicles

ObjectivesUsing of non-steroidal anti-inflammatory drugs in women can cause ovulation dysfunction.It suggests that inhibition of ovarian inflammation signals may impair the normal mechanisms of ovarian follicular development.NF-?B,a classical inflammatory signaling pathway,is involved in a series of normal or abnormal physiological pathways in cells.However,the role of NF-?B in mammalian follicular development remains unclear.Therefore,this article will mainly explore the effect of NF-?B signaling on follicular development.MethodsIn this paper,the knock-in transgene technique was used to mutate a conserved cysteine of p50 to serine,which greatly enhanced the NF-?B DNA-binding activity and established the active NF-?B mouse model.The ovaries were collected and analyzed for ovarian phenotypic differences.By using the morphological staining,immunofluorescence,Q-PCR and Western-blot,we analyzed the differences of all stages follicles and detected many important factors related to ovarian cell proliferation,apoptosis and differentiation.In vitro,we added different concentrations of LPS and Bay11-7082(NF-?B inhibitor)to the COV434 granulosa cell and detected the level of proliferation,apoptosis and differentiation.ResultsThe results showed that the weight and two-dimensional area of ovaries in active NF-?B mouse were not significantly different from normal groups,but more vessel appeared on the ovaries surface in active NF-?B mouse.In active NF-?B mouse,the number of secondary follicles decreased and antral follicles number increased.The expressions of Cyp11a1 and Cyp19a1,which are related to the development of antral follicles,were up-regulated in active NF-?B mouse.In addition,the expression of FSHR and LHR,which are related to differentiation of granulosa cells,were significantly up-regulated compared with the normal group.The expression of Ki67 and PCNA associated with cell proliferation have also been upregulated.However,in active NF-?B mouse,we found that the number of atresia follicles was reduced than in control group,and the expression of apoptosis-related factors,such as Fas,Fasl,and c-caspase3 were decreased.In vitro,the FSHR expression and cell proliferation increased,and apoptotic signal was inhibited in LPS-treated group.On the contrary,the granulosa cell proliferation and the FSHR expression in Bay11-7082-treated group was inhibited,and the apoptosis signal was enhanced.ConclusionNF-?B signaling is likely to be involved in the regulation of follicular development,which mainly affects the transformation of secondary follicle to antral follicle.The activation of NF-?B can promote the proliferation and differentiation of ovarian granulosa cells and inhibit its apoptosis.It can accelerate the transformation of secondary follicles into antral follicles and inhibit the follicle atresia.This process is likely to be related to the promotion of FSHR expression and inhibition of Fas/Fasl expression.