Abstract: Objective To investigate the effects of different doses of transforming growth factorβ1 on temporomandibular joint osteoarthritis (TMJOA) in rabbit model.Methods 40 rabbits were randomly divided into experimental group (36) and control group (4).Partial disc resection was performed bilaterally in 36 rabbits to induce osteoarthritis．Four weeks later,the right joint was injected with 20 ng,40 ng,80 ng TGFβ1 as 20 ng,40 ng,80 ng TGFβ1 groups，and the left joint with physiological saline as physiological saline group.6 and 12 weeks after injection,6 animals of each group were sacrificed and the condyle was dissected to be scanned by microcomputed tomography (microCT) and stained with safraninO to analyze the three dimensional morphology of the subchondral bone and examine the amountof proteoglycan in articular cartilage.Results Joints in physiological saline group after the surgery showed osteoarthritic changes with decreased amount of proteoglycan in articular cartilage and gradually hardened subchondral bone.6 weeks after injection,all TGFβ1 groups had a higher amount of proteoglycan than the normal group and physiological saline group,and the amount of proteoglycan in 40 ng and 80 ng TGFβ1 groups was higher than that in 20 ng group.At 12 weeks,all TGFβ1 groups had a wellorganized fibrocartilage.There was no difference in the amount of proteoglycan between all TGFβ1 groups,while it was still higher than the normal group.The subchondral bones in all TGFβ1 groups have improved and were similar to the normal group.Conclusions Intraarticular injection of TGFβ1 can effectively promote the cartilage repair and prevent abnormal bone remodeling of the subchondral bone in TMJOA.

Key words: transforming growth factorβ1, temporomandibular joint, osteoarthritis, articular cartilage, subchondral bone, New Zealand whiterabbit