Effect Of Static Pressure On The Apoptosis And Proliferation In Cultured Chondrocytes In Vitro

Objective : To investigate the effect of static pressure on the apoptosis and proliferation in cultured chondrocytes in vitro and the relationships between TNF-αor IL-1βand the apoptosis in cultured chondrocytes in vitro.Methods : Articular chondrocytes were isolated from the knees of New Zealand white rabbits and then cultured and passaged to the third generation ,the chondrocytes of the third generation were cultured under different pressure loadings(0kp,20kp,40kp,70kp)at different time (0h,4h,16h,24h)respectively,and then the chondrocytes were collected ,test the apoptosis of the chondrocytes by FCM , PCNA was detected by immunohistochemistry as index of cchondrocyte proliferation.The contents of TNF-αand IL-1βin the culture medium were counted at the same time .Results: At pressure of 20kp or 40kp ,the apoptosis of chondrocytes was improved at the first 4 hours,and then decreased slowly ,but yet exceeded the control group ,the proliferation was inhibited at the first 4 hours and then increased gradaully;at 70kp, the apoptosis of chondrocytes were increased significantly at all time , the proliferation was increased rapidly at the first 4 hours and then inhibited at the following time .the content of TNF-αwas improved with the time lasting especially at 40kp and 70kp, it positively correlated with the apoptosis of chondrocyte ;in this article ,there was no significant relation between the content of IL-1βand the apoptosis of chondrocytes,but at the pressure of 70kp , the content of IL-1βwere decreased gradaully as the hours increased,it negatively correlated with the apoptosis of chondrocyte.Conclusion: At high static pressure and at long-term time ,the nunbers of the chondrocyte would decrease;at a lower pressure at some time the nunbers of the chondrocyte would increase;there were some relationships between the content of TNF-αor that of IL-1βand the apoptosis of chondrocyte; the chondrocytes proliferate obviously under appropriate pressure for some time in medium with certain cytokine.