周期性张应力对骨性关节炎软骨细胞p38 MAPK表达及其磷酸化的影响

Effects of cyclic tensile strain on expression of p38 MAPK and phospho-p38 MAPK in osteoarthritis chondrocytes

目的:观察周期性张应力(cyclic tensile strain,CTS)对兔骨性关节炎(osteoarthritis,OA)软骨细胞中p38丝裂原活化蛋白激酶(p38 MAPK)表达及其磷酸化的影响,探讨力学载荷在骨性关节炎的病理过程中的作用。方法:实验动物行一侧前交叉韧带切断术(ACLT)制作OA动物模型,术后10周消化分离兔膝软骨细胞体外培养,非手术侧软骨细胞为正常组,OA细胞随机分为低应力组、高应力组以及对照组,分别加载0.1 Hz、1.0 Hz、0 Hz的周期性张应力。加载应力24 h、1周和2周后RT-PCR和Western blotting测定各组p38 MAPK及其磷酸化产物表达水平。结果:在各时点各组p38 MAPK均有不同程度的表达,其中加载CTS前,正常组与OA对照组相比差异非常显著(P<0.01);加载CTS 1周后,高应力组与低应力组差异有统计学意义(P<0.05);加载CTS 2周后,低应力组与对照组差异非常显著(P<0.01)。Western blotting显示p38 MAPK磷酸化产物在对照组和OA+高应力组持续表达,而OA+低应力组在24 h、1周、2周3个时点的表达逐渐下降。结论:力学载荷可影响p38 MAPK的表达及磷酸化程度,骨性关节炎的发展发生与应力在细胞分子水平上相互影响。

AIM： To observe the effect of cyclic tensile strain（CTS） on the expression of p38 MAPK and phospho-p38 MAPK in rabbit osteoarthritis（OA） chondrocytes in vitro.METHODS： The animal model of OA was induced by anterior cruciate ligament transection in New Zealand white rabbits.The animals in all groups were evaluated 10 weeks later.The rabbits in OA group were randomly divided into 3 groups,low CTS（0.5 Hz,sin10%,6 h/d） group,high CTS（1.0 Hz,sin10%,6 h/d） group and control group.Both CTS groups were stimulated by a Flexercell-4000 tension system.The expression of p38 MAPK and phospho-p38 MAPK of the chondrocytes was analyzed by RT-PCR and Western blotting at the time points of 24 h,1 week and 2 weeks.RESULTS： The knee joints of the rabbits in OA group had obvious degeneration of articular cartilage.The expression of p38 MAPK in normal group was significantly lower than that in control group（P0.01）,and the difference between low CTS group and high CTS group 1 week after stimulation（P0.05） was observed.Meanwhile,significant difference was found between low CTS group and control group 2 weeks after CTS treatment（P0.01）.The expression of phospho-p38 MAPK was decreased at different time points in low CTS group. CONCLUSION： Different cyclic tensile strains lead to different effects on the expression of p38 MAPK and phospho-p38 MAPK in the chondrocytes.p38 MAPK signaling pathway plays an important role in the development of osteoarthritis in chondrocytes.