The Combined Use of a Graft of Demineralized Bone Matrix along TGF-β1 Leads to an Early Bone Repair in Dogs

Abstract

Tibia fractures are common in small animal practice. Over the past decade, improvements to animal internal fracture fixation have been developed. TGF-β1 has been shown to be crucial in the development, induction and repair of bone. In present study we investigate the effect of local application of a graft demineralized bone matrix along with TGF-β1 in a model of open osteotomy induced experimentally in dogs. Tibia fracture was brought about by using an open osteotomy model in male young dogs. Fracture repair was evaluated by a histological and biochemical analysis. Collagen content, proteolytic activity and urokinase-type plasminogen activators (uPA) expression were analyzed at the end of the study. Radiographical analysis, alkaline phosphatase and hematological evaluation were done weekly. At fifth week, there was an improvement and restoring of bone architecture in animals treated with a graft containing TGF-β1 (5 ng/ml) compared with control and graft groups, as was evidenced by the presence of an early formation of wide callus and bone regeneration. In addition, the local application of TGF-β1 leaded to an increase of collagen and proteolytic activity. There was found more immunopositive osteoclast and mesenchymals cells in bone tissue from animals treated with TGF-β1 as compared with control group. No changes in alkaline phosphatase, hematological and clinical parameters were observed. This study shows that the combined use of DBM along with TGF-β1 is able to improve and accelerate the bone repair.