Inhibition of acid‐sensing ion channels by amiloride protects rat articular chondrocytes from acid‐induced apoptosis via a mitochondrial‐mediated pathway
Inhibition of acid‐sensing ion channels by amiloride protects rat articular chondrocytes from acid‐induced apoptosis via a mitochondrial‐mediated pathway
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DOI：
10.1042/cbi20110432
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发表时间：
2012-07
影响因子：
3.9
通讯作者：
C. Rong;Feihu Chen;Sheng Jiang;Wei Hu;Fan‐rong Wu;Tianyi Chen;Feng-Lai Yuan
中科院分区：
文献类型：
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作者：
C. Rong;Feihu Chen;Sheng Jiang;Wei Hu;Fan‐rong Wu;Tianyi Chen;Feng-Lai Yuan
组织pH值显著降低或酸中毒是许多疾病的共同特征，包括类风湿性关节炎(RA)。关节局部酸中毒对软骨稳态有很大影响。利尿剂阿米洛利在脑缺血模型中具有神经保护作用，这一特性可归因于该药物抑制ASICs(酸敏离子通道)。然而，阿米洛利对胞外酸诱导的关节软骨细胞凋亡的影响却知之甚少。我们发现阿米洛利在体外可以抑制酸诱导的大鼠关节软骨细胞的凋亡。分离、培养原代大鼠关节软骨细胞，用细胞外液(pH 6.0)诱导细胞凋亡，同时加入50~2 0 0μ的M阿米洛利。检测软骨细胞凋亡率、线粒体功能、凋亡相关基因Bcl2家族基因表达水平及caspase3/9活性。阿米洛利以剂量依赖方式抑制软骨细胞的凋亡。此外，阿米洛利通过调节细胞外酸诱导的软骨细胞线粒体膜电位的表达和caspase3/9的活性，部分恢复了线粒体膜电位的水平。我们的结果表明，阿米洛利通过增强抗凋亡能力和下调促凋亡因子，从而保护线粒体功能，从而对酸诱导的大鼠关节软骨细胞凋亡具有保护作用。
A significant decrease in tissue pH or acidosis is a common feature of numerous diseases, including RA (rheumatoid arthritis). Cartilage homoeostasis is profoundly affected by local acidosis in the joints. The diuretic, amiloride, is neuroprotective in models of cerebral ischaemia, a property attributable to the inhibition of ASICs (acid‐sensing ion channels) by the drug. However, little is known about the effect of amiloride on apoptosis induced by extracellular acid in articular chondrocytes. We have found that amiloride could restrain the acid‐induced apoptosis of rat articular chondrocytes in vitro. Primary rat articular chondrocytes were isolated, cultured and induced to apoptose by exposure to extracellular solution (pH 6.0), while simultaneously treated with 50–200 μM amiloride. Apoptotic rate, mitochondrial function, levels of apoptosis‐related gene Bcl‐2 family mRNA and activity of caspase 3/9 in chondrocytes were examined. Amiloride inhibited chondrocyte apoptosis in a dose‐dependent manner. Furthermore, amiloride partly restored the levels of mitochondrial membrane potential by regulation of Bcl‐2 family gene mRNA expression, and activity of caspase 3/9 in chondrocytes induced by extracellular acid. Our results indicated that amiloride protected against acid‐induced apoptosis in rat articular chondrocytes by increasing anti‐apoptotic ability and down‐regulation of pro‐apoptotic factors, thus protecting mitochondrial function.