This study aimed to investigate the expression of B‐cell lymphoma‐extra large (Bcl‐xL) in cartilage tissues following articular cartilage injury and to determine its effects on the biological function of chondrocytes. A total of 25 necrotic cartilage tissue samples and 25 normal tissue samples were collected from patients diagnosed with osteoarthritis at our hospital from December 2015 to December 2018. The mRNA expression levels of Bcl‐xL, caspase‐3, and matrix metalloproteinase‐3 (MMP‐3) in the normal and necrotic tissues were examined via quantitative polymerase chain reaction, and their protein expression levels were detected via western blotting. The expression levels of Bcl‐xL, insulin‐like growth factor‐1 (IGF‐1), and bone morphogenetic protein (BMP) were significantly lower but those of caspase‐3, MMP‐3, interleukin‐1β (IL‐1β), and chemokine‐like factor 1 (CKLF1) levels were markedly higher in necrotic cartilage tissues than in normal tissues. Following cell transfection, the expression levels of Bcl‐xL, IGF‐1, and BMP were remarkably higher but those of caspase‐3, MMP‐3, IL‐1β, and CKLF1 were notably lower in the Si‐Bcl‐xL group than in the NC group. The Si‐Bcl‐xL group showed significantly lower cell growth and noticeably higher apoptosis rate than the NC group (normal control group). The expression of Bcl‐xL is reduced following articular cartilage injury, and this reduction promotes the proliferation and inhibits the apoptosis of chondrocytes. Therefore, Bcl‐xL could serve as a relevant molecular target in the clinical practice of osteoarthritis and other diseases causing cartilage damage.

中文翻译：

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关节软骨损伤后Bcl-xL的表达及其对软骨细胞生物学功能的影响

本研究旨在研究关节软骨损伤后软骨组织中 B 细胞淋巴瘤-特大 (Bcl-xL) 的表达，并确定其对软骨细胞生物学功能的影响。收集2015年12月至2018年12月在我院确诊为骨关节炎患者的25份坏死软骨组织标本和25份正常组织标本。Bcl-xL、caspase-3和基质金属蛋白酶-3（MMP）的mRNA表达水平‐3) 在正常和坏死组织中通过定量聚合酶链反应进行检测，并通过蛋白质印迹检测它们的蛋白质表达水平。Bcl-xL、胰岛素样生长因子-1（IGF-1）和骨形态发生蛋白（BMP）的表达水平显着降低，而caspase-3、MMP-3、白细胞介素-1β（IL-1β）的表达水平显着降低, 和趋化因子样因子 1（CKLF1）水平在坏死软骨组织中明显高于正常组织。细胞转染后，Bcl-xL、IGF-1和BMP的表达水平显着高于Si-Bcl-xL组，而caspase-3、MMP-3、IL-1β和CKLF1的表达水平显着低于Si-Bcl-xL组在NC组。Si-Bcl-xL 组与 NC 组（正常对照组）相比，细胞生长显着降低，细胞凋亡率明显升高。关节软骨损伤后 Bcl-xL 的表达降低，这种降低促进了软骨细胞的增殖并抑制了其凋亡。因此，Bcl-xL 可以作为骨关节炎和其他引起软骨损伤的疾病的临床实践中的相关分子靶标。