Effects Of Different Intensities Of Exercise On Osteoarthritis And The Expression Of Transglutaminase 2 In Cartilage Of Rats

Osteoarthritis?OA?is a chronic joint disease associated with age,nutritional status,joint injury,joint deformity,genetic factors and strenuous exercise.At the same time,several studies suggest that knee OA is the most important age-related disease that may occur after knee injury.It may also affect young,middle-aged,or athletes.And it has a significant impact on people's quality of life.With ongoing worldwide increases in both aging and the size of obese populations,health professionals need a new therapeutic way to treat patients with hip and knee OA.OA can induce pain,stiffness,and even disability of joints.Adequate exercise has been shown to be beneficial in people with OA by relieving pain and increasing mobility.Although physical exercise is one of the most common non-pharmacological OA therapies,the duration and type of exercise programs varied widely.Transglutaminase 2?TG2?is a member of the TG family.It is an enzyme that catalyzes the reaction of Ca²⁺dependent acyltransferases,in which the relationship between TG2 and OA has been confirmed,and it is the main mediator of IL-1?to induce calcification.The accumulation of TG2 in ECM promoted chondrocyte hypertrophy and cartilage calcification.The expression of TG2 in articular cartilage with different exercise intensity was detected by HE staining,immunohistochemistry and Western-blotting.The normal distribution variance homogeneity distribution of each group of data was detected by SPSS20.0 statistical software.One-way ANOVA was used.There was significant difference between control group and OA group?^*P<0.05?.And there was also significant difference between OA group and moderate-intensity treadmill exercise?⁺P<0.05?..The relationship between exercise load and osteoarthritis can provide a new idea for clinical prevention and treatment of osteoarthritis.The results show that moderate aerobic exercise has a beneficial effect on osteoarthritis in rats.Objective:To investigate the expression of articular cartilage under treadmill exercise with different intensities.To explore the role of TG2 by treadmill exercise,and to further study the molecular mechanism of OA.Methods:OA model was established by intra-articular injection of monosodium iodoacetate?MIA?.This method is simple and convenient,which produce pathological changes similar to that of human OA.Fifty male Sprague-Dawley rats were randomly divided into five groups?n=10?:controls?CG?,knee OA model?OAG?,OA+low-intensity treadmill exercise?OAL?,OA+moderate-intensity treadmill exercise?OAM?and OA+high-intensity treadmill exercise?OAH?.1.The cartilage of the five groups was stained with HE.The damage of articular cartilage was observed under microscope and was evaluated by Mankin score.2.The expression of TG2 in cartilage was observed under microscope,and the density of TG2 was measured by image analysis software.The average value of each group was divided into five groups.SPSS software was used to analyze the expression of TG2 in articular cartilage of five groups.3.Five groups of articular cartilage were tested by Western blotting.Chondrocytes were washed twice in ice-cold PBS and sonicated in lysis buffer?P0013C,Beyotime,China?.The relative expression of TG2 was calculated by Image J image analysis software.?-actin was used as the internal control.Results:1.Pathological section showed that the degree of cartilage lesion in moderate-intensity treadmill exercise group?OAM?was significantly lower than that in OA control group,low intensity exercise group and high intensity exercise group.2.Immunohistochemistry showed that the low expression of TG2 in normal control group and the high expression of TG2 in OAG?P<0.05?;the high expression of TG2 in low-intensity treadmill exercise group?OAL?and high-intensity treadmill exercise group?OAH?;The expression of TG2 in moderate-intensity treadmill exercise group?OAM?was significantly lower than that in OAG?P<0.05?.3.Western blotting:the high expression of TG2 in OAG and normal CG?P<0.05?;The expression of TG2 was also higher in OAL and OAH than CG?P<0.05?;The expression of TG2 in OAM was significantly lower than that in OAG?P<0.05?.Conclusion:The expression of TG2 in the OAG compared with CG was significantly increased,which suggested that TG2 may play a role in OA.But the expression of TG2 was significantly decreased in OAM compared to OAG,which suggested that OAM has a beneficial effect on osteoarthritis in rats.