Effect And Mechanism Of Magnesium On Regulating Autophagy In Temporomandibular Joint Osteoarthritis Mediated By OPN

Objective:To investigate the effects of magnesium ions on autophagy and Osteopontin(OPN)in temporomandibular joint osteoarthritis(TMJOA),through established the model of TMJOA.To verify the relationship between the TMJOA recovery,OPN and autophagy.To analyze the optimal concentration and ratio of magnesium ion,and discuss the effect of magnesium on autophagy mechanism and TMJOA recovery.Methods:1.Collect the cartilage tissue from the rats temporomandibular joint.Use enzyme digestion method to get the original generation of chondrocytes.2.Induced inflammatory response by Lipopolysaccharide(LPS),after dose-effect experiment and time-effect experiment of LPS,we determined the concentration and time of LPS in temporomandibular joint chondrocytes.3.The Temporomandibular Joint Osteoarthritis chondrocytes were randomly divided into four groups according to treatment:100ng/ml MgCl2,500ng/ml MgCl2,1μg/ml MgCl2 and culture medium.Detect the expression of LC3 β,the marker of autophagy protein;And dectect the expression of SOD2,NQOD1,TXN 1,the genes which related to autophagy efficiency,by using Real-time PCR.Meanwhile,to detect the expression of mRNA and protein of OPN,IL1-β and TNF-α.Results:1.The cells were polygonal with clearly boundary and roundly and largely nuclei.Until the third generation of chondrocytes,they was basically similar to the primary generation.With the gradually proliferation of chondrocytes,apoptosis and dedifferentiation appeared in the fourth generation.2.The concentration and induction time of LPS to the chondrocytes were determined to 100ng/ml for 24h through the dose-effect experiment and time-effect experiment.3.The higher concentration of MgCl2,the higher expression of LC3β.The expressions of OPN,IL-1β and TNF-α protein and mRNA in temporomandibular joint osteoarthritis chondrocytes were firstly decreased and then increased with the increasing concentration of MgCl2,and the trends of SOD2,NQOD1,TXN1 was consistent with OPN,IL-1β and TNF-α.The expressions of OPN,IL-1β and TNF-α were the lowest in 500ng/mlMgCl2 group.Conclusion:1.We could collect high-purity temporomandibular joint chondrocytes by using enzyme digestion method.2.The inflammatory expression of chondrocytes was related to the concentration and time of LPS.The inflammatory factors were increased and autophagy was inhibited when the final concentration of 100ng/ml LPS was applied to chondrocytes for 24h.3.The concentration of MgCl2 was positively correlated with the expression of autophagy.4.Over activated autophagy may lead to autophagy injury,which is unfavorable to the recovery of temporomandibular joint osteoarthritis.MgCl2 has certain guiding significance for the treatment of temporomandibular joint osteoarthritis.