Objective: To explore the effect of tensile strains on the proliferation, expression of inflammatory factors and Hedgehog pathway molecules of rat mandibular condylar chondrocytes. Methods: Chondrocytes were cultured and identified. All tensile strains were applied to the cells for periods of 4 hours using Flexcell-4000TM strain unit. The amplitude of tensile strains was 0%, 3% and 15% at a frequency of 0.5 Hz respectively. Cell proliferation was measured by CCK-8 method. The mRNA expression of PCNA, Caspase-3, COL II, IL-1β, TNF-α, Ihh, Ptc and Smo were quantified by Real-time PCR. Results: The chondrocytes at 3% tensile strain showed higher speed proliferation, the expression of PCNA, COL II, Ihh, Ptc and Smo were up-regulated. At 15%tensile strains, the expression of Caspase-3, IL-1βand TNF-αwere up-regulated, but PCNA and Smo were down-regulated. Compared with 3% tensile strain, the chondrocytes at 15%tensile strain showed lower speed proliferation, the expression of PCNA, COL II, Ihh and Smo were down-regulated, but Caspase-3 and IL-1βwere up-regulated. Conclusion:The proliferation of chondrocytes and the expression of inflammatory factors may change along with different level of tensile strains. 15% tensile strains could induce the expression of apoptosis and inflammatory factors, 3% tensile strains could cause increase of proliferation of chondrocytes and cartilage matrix synthesis. Meanwhile the molecules of Hedgehog pathway signal are sensitive to tensile strains and may participate in the regulation process of mechanical stimulation on chondrocytes.%目的：观察牵张力对大鼠髁突软骨细胞增殖、炎性因子及Hedgehog通路基因的表达影响，探讨牵张力对软骨细胞的调控。方法：体外培养软骨细胞并鉴定。用Flexcell 4000TM加力板对细胞施加0.5 Hz，0%、3%和15%的牵张应变，作用4 h后检测细胞增殖情况，对比PCNA、Caspase-3、COL II、IL-1β、TNF-α及Hedgehog通路基因Ihh、Ptc和Smo的表达变化。结果：与对照组相比，3%组细胞增殖速度增加，PCNA、COLII、Ihh、Ptc和Smo的mRNA表达增加，15%组Caspase-3、IL-1β和TNF-α表达增加，而PCNA、Smo 表达降低。与3%组相比，15%组细胞增殖速度降低， PCNA、COL II、Ihh和Smo表达降低，而Caspase-3、IL-1β表达增高。结论：不同强度牵张力对大鼠髁突软骨细胞增殖活性及炎性因子表达作用不同。 Hedgehog通路对牵张力敏感，可能参与了力学刺激对软骨细胞的调控。
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