Effects Of Nicotine And Estrogen On The Metabolism Of Extracellular Matrix In Chondrocytes

The main function of chondrocytes is to maintain the balance of matrix metabolism in cartilage tissue.The long-term destruction of matrix metabolic balance can cause damage to cartilage tissue,which leads to a series of joint diseases such as osteoarthritis.There are many drugs that affect the metabolism of chondrocyte matrix,such as nicotine,estrogen,etc.The effects of these drugs on cell metabolism have been controversial in previous reports,and few reports have focused on the cross-effects of these drugs.Therefore,the purpose of this study was to investigate the molecular mechanism of the effects of nicotine and estrogen alone or in combination on the extracellular matrix metabolism of chondrocytes.The study used iron-selenium transfer protein(ITS)induced cartilage precursor ATDC5 cells as a research object,and the biological methods such as cell staining,immunohistochemistry,Western blot and Real-time PCR were used to detect the chondrocyte matrix and key factors in the metabolic process after drug treatment.First,we studied the effects of direct nicotine treatment and estrogen on chondrocyte metabolism.The results showed that direct treatment of nicotine(0.06mM)inhibited the secretion of extracellular matrix of chondrocytes,promoted the expression of matrix-degrading enzyme MMP13 and decreased the expression of matrix-protection protein BMP-7.Estrogen(1nM)has the opposite effect on cells,and it can also reduce the damage of cells from nicotine in the case of simultaneous treatment of both drugs.Later,in order to better simulate the inflammatory state of chondrocytes in early osteoarthritis,we used nicotine to induce inflammatory supernatant produced by macrophages to induce inflammation of chondrocytes,and further studied estrogen and inflammatory factors in which cells were impact.Studies have shown that nicotine-induced inflammatory supernatants promote the degradation of extracellular matrices,including type II collagen,aggrecan and PRG4.In the presence of physiological concentrations of estrogen,this destructive effect is reduced.At the molecular level,treatment of cells with only estrogen inhibits the matrix-degrading enzymes MMP13 and ADAMTS-5,facilitating the TGF-β1 pathway involved in matrix synthesis.However,in the presence of inflammation induction,although estrogen inhibits the expression of matrix degrading enzymes,it inhibits the TGF-β1 pathway.Therefore,we hypothesized that estrogen reverses nicotine-induced inflammation primarily by reducing the degradation of the extracellular matrix of chondrocytes.In addition,different inflammatory factors in the inflammatory supernatant,mainly TNF-α,IL-1β,have different effects on the metabolic process of chondrocytes.The cross-effects of estrogen,nicotine and inflammatory factor inhibitors found in the study may provide some reference for the early clinical prevention and treatment of patients with osteoarthritis.