OBJECTIVETo study the effects of kneepad on expression of Bcl-2 and p53 mRNA of chondrocyte in white rabbits with knee osteoarthritis, so as to explore and treatment mechanism of OA kneepad on apoptosis of chondrocytes of rabbits with knee osteoarthritis in molecular degree.

METHODSForty-four Japanese healthy 6-month-old rabbits (equal male and female,the weight ranging from 2 to 2.2 kg) were used to establish knee osteoarthritis models by modified Hulth method. The rabbits were randomly divided into 6 groups: normal group, model group, control group (microwave), experimental group 1 (electricity), experimental group 2 (thermal), experimental group 3 (kneepad). Ten rabbits in the normal group were breed with conventional method; 9 rabbits in the model group were breed with conventional method after model made; 9 rabbits in the control group were treated with microwave for 30 minutes, one time daily; 9 rabbits in the experimental group 1 were treated with electricity (density wave) for 30 minutes,one time daily;8 rabbits in the experimental group 2 were treated with hot (hot soft membrane) for 30 minutes, one time daily; 9 rabbits in the experiment group 3 were treated with electrothermal (OA knee pad) for 30 minutes, one time daily. All the rabbits were treated for 16 weeks and then sacrificed. The expressions of Bcl-2 and p53 mRNA of chondrocytes in knee joint were detected by using fluorescence quantitative RT-PCR method.

RESULTSAt the 16 hthek,th e OD260/OD280 value range of total RNA extracted from rabbit articular cartilage tissue in each group were all at 1.80 to 2.00,wh ich indicates high RNA purity. The p53 relative mRNA in articular cartilage cells of model group,th e control group,th e experimental group 1 ,r oup 2,gr oup 3 were overexpressed,an d Belc2 mRNA expression levels of articular cartilage cells were low expression,an d compared with the normal group there were significant differences (P < 0.01). Belc2, p53 mRNA expression in articular cartilage cells,th ere were significant differences (P < 0.01) between the control group, experimental group 1, group 2, group 3 and model group. The results between the control group, experimental group 1 ,group 2 and group 3 had significant differences (P < 0.01).

CONCLUSIONOA-kneepad can up-regulate the mRNA expression of Bcl-2 as well as down-regulate the mRNA expression of p53, thereby to inhibit the apoptosis of cartilage cells and delay the degeneration of articular cartilage changes.