RESUMO
BACKGROUND:Internal heat-type acupuncture therapy is a new treatment technique that combines acupuncture therapy with hyperthermia.It has good clinical effects on steroid-induced osteonecrosis of the femoral head,but the mechanism of action is still not fully clear. OBJECTIVE:To explore the possible mechanism of internal heat-type acupuncture therapy in treating steroid-induced osteonecrosis of the femoral head in rabbits. METHODS:Thirty-two New Zealand rabbits were randomly divided into blank group,model group,internal heat-type acupuncture group and shock wave group using a random number table method,with 8 rabbits in each group.The model group,internal heat-type acupuncture group and shock wave group were modeled using methylprednisolone sodium succinate combined with Escherichia coli endotoxin.The internal heat-type acupuncture group received an internal heat-type acupuncture intervention on the buttocks of rabbits,once a week,for 20 minutes each time.The shock wave group received shock wave intervention on the buttocks of rabbits,once a week,with 2 000 beats per session.The blank group and model group were not given any treatment.After 4 weeks of intervention,blood samples and bilateral femoral head samples were collected from experimental rabbits.The levels of tumor necrosis factor-α and interleukin-6 in serum were detected by ELISA;the histomorphology of the femoral head was observed using hematoxylin-eosin staining and the rate of empty lacunae was calculated;the protein expressions of matrix metalloproteinase 2,matrix metalloproteinase 9,matrix metalloproteinase tissue inhibitor 1,and matrix metalloproteinase tissue inhibitor 2 were detected by immunohistochemistry and western blot. RESULTS AND CONCLUSION:Compared with the blank group,the model rabbits showed reduced food intake,mental fatigue,and decreased activity;compared with the model group,the above performance of the experimental rabbits was significantly improved after internal heat-type acupuncture and shock wave treatment.Compared with the blank group,the histomorphology of the femoral head in the model group deteriorated significantly and the rate of empty bone lacuna increased(P<0.001),while the histomorphology of the femoral head in the internal heat-type acupuncture group and shock wave group was significantly improved compared with the model group,and the rate of empty bone lacuna was reduced(P<0.001).The serum levels of tumor necrosis factor-α and interleukin-6 in the model group were significantly higher than those in the blank group(P<0.05),while the serum levels of tumor necrosis factor-α and interleukin-6 in the internal heat-type acupuncture group and the shock wave group were significantly lower than those in the model group(P<0.05).Compared with the blank group,the expression levels of matrix metalloproteinase 2 and matrix metalloproteinase 9 in the femoral head of the model group were significantly increased,while the expression levels of matrix metalloproteinase tissue inhibitor 1 and matrix metalloproteinase tissue inhibitor 2 were significantly decreased(P<0.001);compared with the model group,the protein expression levels of matrix metalloproteinase 2 and matrix metalloproteinase 9 were significantly decreased,while the protein expression levels of matrix metalloproteinase tissue inhibitor 1 and matrix metalloproteinase tissue inhibitor 2 were significantly increased in the internal heat-type acupuncture group and the shock wave group(P<0.001).Overall,these findings indicate that internal heat-type acupuncture may promote the repair of the necrotic femoral head by regulating the levels of matrix metalloproteinases/matrix metalloproteinase tissue inhibitors and serum inflammatory factors,thus treating early steroid-induced osteonecrosis of the femoral head.