Extracorporeal shockwave therapy shows a number of treatment related chondroprotective effect in osteoarthritis of the knee in rats

BACKGROUND Extracorporeal shockwave therapy (ESWT) shows chondroprotective effect in osteoarthritis of the rat knees. However, the ideal number of ESWT is unknown. This study investigated the effects of different numbers of ESWT in osteoarthritis of the knee in rats. METHODS Forty-five male Sprague-Dawley rats were divided into five groups. Group I underwent sham arthrotomy without anterior cruciate ligament transection (ACLT) or medial meniscectomy (MM) and received no ESWT. Group II underwent ACLT + MM and received no ESWT. Group III underwent ACLT + MM, and received ESWT once a week for one treatment. Group IV underwent ACLT + MM and received ESWT twice a week for 2 treatments. Group V underwent ACLT + MM and received ESWT three times a week for 3 treatments. Each treatment consisted of 800 impulses of shockwave at 14 Kv to the medial tibia condyle. The evaluations included radiographs of the knee, histomorphological examination and immunohistochemical analysis at 12 weeks. RESULTS At 12 weeks, group II and V showed more radiographic arthritis than groups I, III and IV. On histomorphological examination, the Safranin O matrix staining in groups III and IV are significantly better than in groups II and V, and the Mankin scores in groups III and IV are less than groups II and V. Groups III and IV showed significant decreases of Mankin score and increase of Safranin O stain as compared to group I. Group V showed significant increases of Mankin score and a decrease of Safranin O stain as compared to group II. In articular cartilage, group II showed significant increase of MMP13 and decrease of collagen II as compared to group I. Groups III and IV showed significant decrease of MMP13 and increase of collagen II as compared to group I. Group V showed significant increase of MMP13 and decrease of collagen II as compared to group II. In subchondral bone, vWF, VEGF, BMP-2 and osteocalcin significantly decreased in groups II and V, but increased in groups III and IV relative to group I. CONCLUSIONS ESWT shows a number of treatment related chondroproctective effect in osteoarthritis of the knee in rats.