目的观察尾部悬吊模拟失重大鼠细胞因子TNF-α表达水平,探讨失重对颞下颌关节的影响机制。方法选用SD大鼠60只,在模拟应激条件下建立颞下颌关节的失重应激反应动物模型,提取连续刺激1、3、5周。运用ELISA法和RT-PCR测量髁突软骨细胞中TNF-α的含量和TNF-αmRNA的表达量。结果 TNF-αmRNA在失重后1周表达最强,以后逐渐达到正常水平。结论失重能使髁突软骨TNF-α改变,可能促使颞下颌关节发生病变。 Objective To observe the expression of cytokine TNF-α in tail-suspended simulated weightless rats and to explore the mechanism of the effects of weightlessness on temporomandibular joint. Methods Sixty Sprague Dawley rats were used to establish the animal model of temporomandibular joint weightlessness stress response under simulated stress conditions. The rats were continuously stimulated for 1, 3, 5 weeks. The content of TNF-α and the expression of TNF-αmRNA in condylar chondrocytes were measured by ELISA and RT-PCR. Results The expression of TNF-α mRNA was the highest at 1 week after weightlessness, and then gradually reached the normal level. Conclusion Weightlessness can change the condylar cartilage TNF-α, may lead to temporomandibular joint lesions.