The Effevt Of 17?-Estradiol Regulates Rat Nucleus Pulposus Cells Autophagy In Intervertebral Disc Degeneration

Objective:17?-Estradiol(E2)have been noted to protect intervertebral disc(IVD)cells against unphysiological apoptosis.Autophagy and apoptosis play a paramount role in maintaining the homeostasis of IVD cells.So far,little research has been published on whether autophagy could take place at this very moment when E2 provides protection for nucleus pulposus cell.Our aims were to study the effect of E2 on the relationship between autophagy and apoptosis in the IVD cells under serum deprivation and to provide molecular mechanism support for the prevention and treatment of disc degeneration.Methods : Rat nucleus pulposus cells(NPCs)were isolated from the IVD and cultures with or without serum under the experimental conditions.primary nucleus pulposus cells of SD rats was cultured and satined with Alcian blue? toluidine blue and immunocytochemistry.m Cherry-GFP-LC3-adenovirus transfection is used as a mark for autophagy detection.The expression levels of autophagy-related proteins(Beclin-1,microtubule associated protein 1 light chain3(LC3))were measured by Western blotting,Apoptosis and Matrix Metalloproteinase(MMP)were detected by flow cytometry and Western blotting.Results:Autophagy and apoptosis was detected in NP cells under serum deprivation conditions,the total number of apoptosis cells under serum deprivation conditions showed a time-dependent increase over 12 h and the autophagy incidence began to reached a peak value at 48 h,Up-regulated the autophagy incidence and reduced the apoptosis incidence in the NPCs when E2 alone was used under serum starvation for48 h,And the apoptosis incidence began reached a minimum value treat with E2 (10-7M).Whereas the combined use of E2 and 3-MA led to a dramatic decrease in autophagy,while aberrantly elevated expression levels of apoptotic and MMP.These data suggest that E2 could protect against apoptosis through up-regulation of level autophagy in the NPCs under serum deprivation.Conclusion : This research demonstrated that serum deprivation-induced mitochondrial apoptosis and MMP-3,MMP-13,which was efficiently suppressed by the E2 through promoting autophagy in rat NPCs;E2 may have potential protective effect of intervertebral disc degradation.