中文摘要：

目的：探讨不同胞外pH环境对体外培养的大鼠关节软骨细胞增殖、凋亡的影响，以及大鼠关节软骨细胞中组织蛋白酶K的表达与胞外酸化的关系。方法：Ⅱ型胶原酶消化法从大鼠关节软骨中分离软骨细胞；细胞传代培养后分为4组分别在pH7．4、pH、6．5、PH6．0、pH5．5不同的胞外酸化环境下培养3h，MTT法检测软骨细胞活力，Hoechst33258染色观察细胞凋亡形态，Annexin-V／PI双染法检测软骨细胞的凋亡率，实时荧光定量PCR检测组织蛋白酶K基因的表达。结果：与PH7．4组比较其他各组软骨细胞增殖均受到抑制，其中pH5．5、pH6．0与pH7．4相比差异有重要的统计学意义（P〈0．01），PH5．5和pH6．0组可见较多的凋亡细胞，且流式细胞仪检测的凋亡率明显高于pH7．4组（P〈0．01）；组织蛋白酶K的表达与酸性程度成正相关。结论：胞外酸化环境下能明显抑制体外培养软骨细胞增殖、促进软骨细胞凋亡，并且酸性环境能增加组织蛋白酶K的表达，这为类风湿关节炎中关节软骨的破坏发生机制提供了实验依据。

英文摘要：

ABSTRACT AIM： To investigate tile effects of various extracellular solutions on rat chondro cytes proliferation and apoptosis in uitro, and relation of Cathepsin K mRNA expression and exlracellular acidosis. METHODS： Articular chondrocytes were obtained from rats using type II collagenase digestion method. The chondro- cytes were divided into four groups and incuba ted in different pH extracelluar solution （pH 7.4, pH 6.5, pH 6.0, pH 5.5） for three hours. MTT assay was enH）loyed to determine the proliferation of articular chondrocytes in acidic solu- tions. Effects of extracellular acidosis on chon- drocyte apoptosis were observed by Hoechsl 33258 and Annexin V/PI staining. The expres- sion of Cathepsin K mRNA were detected by re al time reverse transcription PCR. RESULTS：Proliferation of articular cbondrocytes were in- hibited observably by acidosis （P〈0. 05）. Ap- optosis rate of articular chondrocytes were increased comparing with controI group （P〈 0.05）. The expression of Cathepsin K mRNA level gradually increased following the degree of acidity in extracellular solution. CONCLUSION： Extracellular acidosis can restrain the prolifera- tion and promote the apoptosis of articular chon drocytes K vitro, and increase the expression of Cathepsin K mRNA, It has provided an experi mental evidence on mechanism bone destruction in Rheumatoid arthritis.