Ⅲ类压应力作用对大鼠髁突软骨增殖和凋亡的影响

Proliferation and Apoptosis of Chondrocytes in Rats' TMJ under ClassⅢ Compressive Stress

目的:探讨Ⅲ类压应力作用下髁突软骨细胞增殖、凋亡以及与软骨改建过程之间的联系。方法:45只大鼠随机分为对照,轻力,重力3组,各组1、3、7d分别处死5只,取双侧颞下颌关节,作HE,Ki67免疫组化以及TUNEL法测软骨细胞凋亡。结果:加力时髁突软骨变薄,其中轻力组髁突软骨适应性改建,重力组发生病理变化。应力作用下的软骨细胞增殖能力下降。轻力作用时软骨细胞凋亡先增加后下降;重力作用下细胞凋亡逐渐增加。结论:适宜大小Ⅲ类压应力作用时软骨细胞增殖和凋亡逐渐平衡,髁突软骨适应性改建;超生理范围压应力作用下髁突软骨的病理变化是由细胞增殖和凋亡失衡引起的。软骨细胞的增殖和凋亡在压应力加载下髁突软骨环境的内稳态维持中有重要作用。

Objective：To investigate the proliferation and apoptosis of chondrocytes in TMJ of rats under the classⅢ compressive stress and study their relationship with the reconstruction of the condyle.Methods：Forty five six weeks old rats were randomly divided into 3groups,including control group,light force group and heavy force group.The condylar cartilage was dissected after 1day,3days and 7days.HE was applied to observe the structure of the condyles.Immunohistochemical staining was used to qualitively examine the Ki67 positive cell,and TUNEL was chosen to detect the apoptotic cell.Results：The condylar cartilage became thinner under the compressive stress.Cartilage restructed in the light force group while pathological change happened in the heavy force group.The number of proliferating cell decreased in both experimental groups.The number of apoptotic cell in condylar cartilage in light-force group increased at the beginning and reduced gradually.However,the number increased in the heavy-force group by and by.Conclusion：Apropriate compressive stress leaded to the balance of proliferation and apoptosis of chondrocyte in condylar cartilage and restruction of the cartilage,while excessive stress resulted in imbalance and pathological change.Equilibrium of proliferation and apoptosis played an important role in the homeostasis of cartilage under compressive stress.