Expression Of Connexin43 In Articular Cartilage Of Rats With Type 2 Diabetes Mellitus

Objective: To investigate the pathological changes and the expression of connexin43(Cx43)in articular cartilage of rats with type 2 diabetes mellitus(T2DM)for better understanding the pathogenesis of diabetic osteoarthritis(OA).Methods: Male Zucker diabetic fatty(ZDF)rats(n = 40)with a fasting blood glucose level above 7.8 mmol/L were served as T2 DM group,and age-matched control lean Zucker rats(LZR)(n = 30)with nondiabetic were served as the control.At the end of 8th,12 th,16th,20 th and 24 th week after the T2 DM model were built,an experimental subgroup and a control subgroup were executed in batches and the bilateral knee and hip joints were obtained.Paraffin sections were made from the cartilage tissues which were cut off from the medial femoral condyles,tibial medial plateaus,and femoral heads for Safranin O staining and immunohistochemistry experiments.The damage of cartilages and the expression of Cx43 in cartilage which were assessed by Mankin’s score and immunohistochemistry,respecively,were analyzed statistically.Results:(1)The Mankin’s scores and the expression of Cx43 in the cartilages of the medial femoral condyles,tibial medial plateaus,and femoral heads tended to increase with the course of T2DM(r=0.786、0.845、0.785,all P<0.001).(2)At the end of 16 th,20th and 24 th week after the T2 DM model were built,the Mankin’s scores and the expression of Cx43 in the cartilages of the femoral heads were smaller than those of the medial femoral condyles and tibial medial plateaus(all P<0.05),while the differences between the cartilages of the medial femoral condyles and tibial medial plateaus were not found(all P>0.05).(3)At the end of 8-24 weeks after the T2 DM model were built,the Mankin’s scores and the expression of Cx43 in the cartilages of the medial femoral condyles and tibial medial plateaus of the T2 DM rats were larger than those of the control rats(all P<0.05).Whereas,the Mankin’s scores and the expression of Cx43 in the cartilages of the femoral heads were larger than those of the control rats at the end of 16-24 weeks after the T2 DM model were built(all P<0.05).Conclusion: The expression of Cx43 in the cartilages of the knee and hip joints of rats with T2 DM tends to increase with the course of T2 DM,and has a positive correlation with the damage of the cartilage,which suggest that the high expression of Cx43 in the cartilages could accelerate the occurrence and development of diabetic OA.