Moxibustion Down-regulates The P38 MAPK Signaling Pathway And Inhibiting Chondrocyte Pyroptosis In The Rat Knee Osteoarthritis Model

Objective: The aim of the study was to investigate the effect of moxibustion intervention on articular cartilage and subchondral bone of SD rat knee osteoarthritis model,and to determine the molecular mechanism of regulating the chondrocyte dysfunction by P38 MAPK and chondrocyte pyroptosis signal pathway.Methods: Twenty-four 3-month-old male SD rats with a body mass of 220-250 g were randomly divided into three groups :the sham-operated group,an ACLT group(the osteoarthritis model group),the moxibustion-treated group(ACLT + moxibustion treatment group),8 rats in each group.The bilateral anterior cruciate ligament resection(ACLT)was used to construct an animal model of traumatic knee osteoarthritis in ACLT group and moxibustion-treated group.The steps in the sham operation group were the same except that the anterior cruciate ligament was not severed.The moxibustion group started intervention two week after the operation.The frequency of intervention was five times a week and the intervention lasted for 30 minutes each time.The intervention time was 8 weeks.The sham-operated group and the osteoarthritis model group did not accept the intervention.After the whole moxibustion intervention,SD rats in each group were killed.HE and Saffron O staining was performed on knee cartilage of SD rats in each group to make pathological sections and perform Mankin Scores,Micro-CT scanner was performed in Subchondral bone at Shanghai Synchrotron Radiation Facility.The expression of IL-1??IL-18?NO in serum was detected by ELISA method.Western blot were used to detect the relative expression of p38?p-p38?NLRP3?Caspase-1?ASC?GSDMD?GSDMD-N?MMP13?ADAMTS5?Sox9 protein of cartilage tissue.Results:1.Compared with the sham-operated group,the Mankin score of the ACLT group was significantly increased(p < 0.01),while the moxibustion-treated was significantly lower than the ACLT group(p <0.01).2.Compared with the sham-operated group,BV/ TV?Tb.Th and Tb.N in the ACLT group decreased significantly(p <0.05,p <0.05,p <0.01),while Tb.Sp increased significantly,with statistical differences.(p< 0.01);BV/TV ? Tb.Th and Tb.N increased significantly in the moxibustion-treated group compared with the ACLT group,with statistical differences(p<0.05,p<0.05,p<0.05),and Tb.Sp decreased significantly,and there was statistical significance(p <0.01).3.Compared with the sham-operated group,the expression of IL-1? in the ACLT group was lower(p <0.05),and the expression of IL-18 increased,but there was no statistical difference(p>0.05).Compared with the ACLT group,the expressions of IL-1? and IL-18 in the moxibustion-treated group rats were significantly decreased and statistically significant(p <0.05,p <0.01).4.Compared with the sham-operated group,the expression levels of p-p38?NLRP3?Caspase-1?ASC?GSDMD?GSDMD-N?MMP13 and ADAMTS5 protein in the ACLT group were significantly increased(p <0.01,p <0.01,p <0.01,p<0.01,p <0.01,p <0.01,p<0.01,p <0.01),the expression of Sox9 protein was significantly reduced(p <0.01);compared with the ACLT group,the expression levels of p-p38 ? NLRP3 ?Caspase-1?ASC?GSDMD?GSDMD-N?MMP13 and ADAMTS5 protein in the moxibustion-treated group were significantly reduced(p <0.01,p <0.01,p <0.01,p <0.01,p <0.01,p <0.01,p <0.01,p <0.01),there was no significant difference in Sox9 protein expression(p> 0.05).Conclusion: 1.Moxibustion intervention has protective effect on articular cartilage of SD rat knee osteoarthritis model,and regulate the subchondral bone remodeling.2.Moxibustion may down-regulate the p38 MAPK signaling pathway and inhibit chondrocyte pyroptosis,and reduce the degradation of cartilage extracellular matrix and maintain the functional integrity of cartilage effectively.