MiR-17-5p Regulates The Degradation Of The Extracellular Matrix Of Nucleus Pulposus Via IL-6/STAT3 Signaling Pathway

Objective: At present,there is a lack of very effective treatment methods for disc degenerative diseases.With the development of molecular biology,gene therapy has gradually begun to treat disc degeneration diseases.Mi RNA is a small molecule non-coding RNA and involved in the pathophysiology of many diseases,such as tumor cell proliferation,osteoblast differentiation,and nucleus pulposus cell apoptosis.Previous studies have shown that mi RNA-17-3p in the mi RNA-17 family is underexpressed in degenerated nucleus pulposus cells and affects degeneration of the disc,and mi RNA-17-5p is also a member of the mi RNA-17 family,which is expressed in multiple tissues and shows different functions in different tissues.However,whether it is expressed in degenerated intervertebral discs and its potential role in the progression of intervertebral disc degeneration has not yet been shown.The purpose of this study was to investigate whether mi RNA-17-5p is abnormally expressed in degenerated intervertebral discs and explore the possible mechanisms that affect the degradation of the extracellular matrix of the nucleus pulposus.Methods: The expression level of mi RNA-17-5p in clinical samples was detected by RT-q PCR,and the correlation between the expression level and the degree of disc degeneration was analyzed.Nucleus pulposus cells were treated with IL-6 at different concentrations(0ng / ml,1ng / ml,10 ng / ml)to simulate a model of inflammatory injury.CCK-8 was used to analyze the nucleus pulposus at different times(4h,12 h,24h,36 h,48h)cell viability,and the effect of IL-6 on the expression levels of mi RNA-17-5p,IL-1,TNF-α and MMP-3 was analyzed by RT-q PCR.The effects of mi RNA-17-5p on inflammatory mediators(L-6,IL-1,TNF-α)and downstream proteins(p-STAT3,MMP-2)were analyzed by Western Blot.Results: The expression level of mi RNA-17-5p was significantly reduced in the intervertebral disc degeneration(P <0.01).And the expression level of mi RNA-17-5p continued to increase as the degree of disc degeneration increased Decreased,there was a significant negative correlation between the two groups(r =-0.95,P <0.01).We found no significant difference between the two groups(IL-6 1ng / ml group and the blank control group)(24h,48 h,P> 0.05),and the IL-6 10 ng / ml group has a significantly lower cell number than the blank control group(24h,36 h,48h,P <0.05).In subsequent experiment,RT-q PCR showed that IL-6 treatment significantly reduced the expression of mi R-17-5p(P <0.05),but significantly increased IL-1,TNF-α(P <0.05),and MMP-3(P <0.01).IL-1,IL-6,and TNF-α expression levels were significantly reduced in mi R-17-5p mimics(P <0.01),while mi R-17-5p inhibitor Significantly increased(P<0.01).Western blot results showed that the levels of ACAN and COL2A1 decreased in the mi R-17-5p inhibitor group,and increased significantly in the mi R-17-5p mimics group(P <0.05);in contrast,the levels of p-STAT3 and MMP-2 were increased in the mi R-17-5p inhibitor group,and significantly reduced in the mi R-17-5p mimics group(P<0.05).Conclusion: Low expression of mi R-17-5p can promote the inflammatory response in nucleus pulposus cells and the degradation of the extracellular matrix,which may activate the IL-6 / STAT3 signaling pathway and promote the secretion of matrix metalloproteinase 3(MMP-3)in the intervertebral disc degeneration.