JAK2/STAT3信号通路介导薯蓣皂苷元对骨性关节炎软骨细胞代谢的影响

Protective effect of diosgenin on chondrocytes mediated by JAK2/STAT3 signaling pathway in mice with osteoarthritis

目的：在小鼠骨性关节炎（OA）模型中观察薯蓣皂苷元（Dgn）通过酪氨酸蛋白激酶2／信号转导子和转录激活子3（JAK2／STAT3）信号通路对软骨细胞代谢和线粒体抗氧化应激能力的影响，以及Dgn在此过程中的作用。方法：15只C57BL／6小鼠随机分为健康对照组、模型对照纽和Dgn组，相应处理4周后取材，采用免疫组织化学法观察各组大体标本形态学变化，电子显微镜下观察软骨组织超微结构变化。将模型对照组培养软骨细胞随机分为四组：①模型对照组；②Dgn组；@Dgn＋阻断剂组；④阻断剂对照组。运用蛋白质印迹法检测各纽软骨细胞中P-JAK2、p-STAT3、Bax、琥珀酸脱氢酶（SDH）和细胞色素C氧化酶（COX）蛋白表达，并用比色法测定线粒体中超氧化物歧化酶（SOD）的含量及活性。结果：软骨组织形态学方面，模型对照组软骨细胞变化最明显，Dgn组细胞形态维持较好，软骨细胞膜完整；电镜下观察发现，模型对照组软骨组织标本表面损伤较为严重，而Dgn组软骨组织标本表面平整。与模型对照组比较，Dgn组p-JAK2、PSTAT3蛋白表达水平上升（均P〈0．05），Bax蛋白表达水平降低（P〈0．05），SDH、COX蛋白表达水平、SOD含量均较模型对照组增加（均P〈0．05）；而与Dgn组比较，Dgn＋阻断剂组P．JAK2和P-STAT3蛋白的表达减少，Bax蛋白表达增加，SDH、COX蛋白表达水平及SOD含量降低（均P〈0．05）。结论：JAK2／STAT3信号通路与OA软骨细胞病理变化密切相关。Dgn可以通过激活JAK2／STAT3通路，有效减轻OA病理过程中软骨细胞的线粒体氧化应激损伤和细胞凋亡，发挥对OA软骨细胞的保护作用。

Objective ： To investigate tile effect of diosgenin （Dgn） on chondrocytes and its relation to JAK2/STAT3 signaling pathway in mice with osteoarthritis （OA）. Methods： Fifteen male C57BL/6 mice were randomly divided into three groups： control group, OA group and OA ＋ Dgn group. After 4 weeks of treatment, the histopathological changes of cartilage tissue were observed by toluidine blue staining under light microscopy and the ultrastructure of chondrocytes was observed under electron microscopy. The primarily cultured chondrocytes of OA mice were randomly divided into 4 groups ： （ 1 ） OA group, （2） Dgn group, （ 3 ） Dgn ＋ AG490 group, （4） AG490 group. The expression of p-JAK2, p-STAT3, Bax, succinate dehydrogenase （SDH） and cytochrome c oxidase （COX） were detected by Western blotting, and superoxide dismutase （SOD） was detected using colorimetric method. Results： The morphological observation showed that the chondrocytes of OA group presented considerable pathological changes, while the chondrocytes in OA ＋ Dgn group maintained intact membrane. Electron microscopy observation found obvious injury in cartilage tissues of OA group, while that in OA ＋ Dgn group remained smooth. Compared with OA group, the expressions of p-JAK2 and p-STAT3 in chondrocytes of Dgn group were increased （ all P 〈 0.05 ） , and the expressions of Bax protein, SDH, COX and SOD were decreased （ all P 〈 0.05）. While compared with Dgn group, the expressions of p-JAK2, p-STAT3, SDH, COX and SOD in chondrocytes of Dgn ＋ AG490 group were decreased （all P 〈 0.05 ）, and the expression of Bax protein was increased （P 〈 0. 05 ）. Conclusion： Diosgenin can inhibit apoptosis and increase mitochondrial oxidative stress capacity of chondrocytes in mice with osteoarthritis, which is closely related to the activation of JAK2/STAT3 signaling pathway.