Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan.
J Orthop Res. 2010 Feb;28(2):156-63. doi: 10.1002/jor.20976.
We investigated whether N-acetylcysteine (NAC), a precursor of glutathione, could protect rabbit articular chondrocytes against nitric oxide (NO)-induced apoptosis and could prevent cartilage destruction in an experimental model of osteoarthritis (OA) in rats. Isolated chondrocytes were treated with various concentrations of NAC (0-2 mM). Apoptosis was induced by 0.75 mM sodium nitroprusside (SNP) dehydrate, which produces NO. Cell viability was assessed by MTT assay, while apoptosis was evaluated by Hoechst 33342 and TUNEL staining. Intracellular reactive oxygen species (ROS) and glutathione levels were measured, and expression of p53 and caspase-3 were determined by Western blotting. To determine whether intraarticular injection of NAC prevents cartilage destruction in vivo, cartilage samples of an OA model were subjected to H&E, Safranin O, and TUNEL staining. NAC prevented NO-induced apoptosis, ROS overproduction, p53 up-regulation, and caspase-3 activation. The protective effects of NAC were significantly blocked by buthionine sulfoximine, a glutathione synthetase inhibitor, indicating that the apoptosis-preventing activity of NAC was mediated by glutathione. Using a rat model of experimentally induced OA, we found that NAC also significantly prevented cartilage destruction and chondrocyte apoptosis in vivo. These results indicate that NAC inhibits NO-induced apoptosis of chondrocytes through glutathione in vitro, and inhibits chondrocyte apoptosis and articular cartilage degeneration in vivo.
我们研究了 N-乙酰半胱氨酸（NAC），一种谷胱甘肽的前体，是否可以保护兔关节软骨免受一氧化氮（NO）诱导的凋亡，并可以防止大鼠骨关节炎（OA）实验模型中的软骨破坏。分离的软骨细胞用不同浓度的 NAC（0-2mM）处理。用 0.75mM 硝普酸钠（SNP）脱水诱导凋亡，产生 NO。通过 MTT 测定评估细胞活力，而通过 Hoechst 33342 和 TUNEL 染色评估凋亡。测量细胞内活性氧（ROS）和谷胱甘肽水平，并通过 Western blot 测定 p53 和 caspase-3 的表达。为了确定关节内注射 NAC 是否可以防止体内软骨破坏，OA 模型的软骨样本进行 H&E、Safranin O 和 TUNEL 染色。NAC 可预防 NO 诱导的凋亡、ROS 过度产生、p53 上调和 caspase-3 激活。谷胱甘肽合成酶抑制剂丁硫氨酸亚砜显著阻断 NAC 的保护作用，表明 NAC 的凋亡预防活性是通过谷胱甘肽介导的。使用实验诱导的 OA 大鼠模型，我们发现 NAC 还可显著防止体内软骨破坏和软骨细胞凋亡。这些结果表明，NAC 通过谷胱甘肽在体外抑制 NO 诱导的软骨细胞凋亡，并在体内抑制软骨细胞凋亡和关节软骨退化。
