Objective: The aim of this work was to determine the effect of miR-375 on chondrocyte metabolism and oxidative stress in osteoarthritis (OA) mouse models through the JAK2/STAT3 signaling pathway. Methods: Chondrocytes were divided into control, IL-1β, IL-1β + miR-375 mimic, IL-1β + miR-375 inhibitor, IL-1β + miR-NC (negative control), and IL-1β + miR-375 inhibitor + siJAK2 groups. The chondrocyte proliferation was determined by MTT assay, the superoxide dismutase (SOD) and malondialdehyde (MDA) levels by corresponding kits, and the chondrocyte apoptosis by TUNEL staining. Furthermore, OA mouse models were divided into Sham, OA + miR-NC, and OA + miRNA-375 antagomir groups. The pathological changes were observed, and the expressions of miR-375 and the JAK2/STAT3 pathway were determined by qRT-PCR and Western blotting, respectively. Results: IL-1β-induced chondrocytes had significant increases in miR-375 and MDA, with decreased proliferation and SOD levels, as compared to the control group. Meanwhile, they also exhibited elevated apoptosis, with upregulations of ADAMTS-5 and MMP-13 and downregulations of COL2A1 and ACAN, as well as decreased p-JAK2/JAK2, p-STAT3/STAT3, and Bcl-2/Bax. However, these changes were significantly improved after transfection with miR-375 inhibitor, but transfection with miR-375 mimic resulted in severer exacerbation. Notably, the improvement of miR-375 inhibitor could be abolished by transfection with siJAK2. Furthermore, miR-375 antagomir significantly alleviated OA progression in OA mice in vivo. Conclusion: MiR-375 suppression enhanced the ability of chondrocyte to antagonize the oxidative stress and maintained the homeostasis of extracellular matrix metabolism to protect chondrocytes from OA via activation of the JAK2/STAT3 pathway, indicating that miR-375 is a potential molecular target for OA treatment.

中文翻译：

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MiR-375 通过 JAK2/STAT3 信号通路介导骨关节炎小鼠模型中的软骨细胞代谢和氧化应激

目的：本工作的目的是通过 JAK2/STAT3 信号通路确定 miR-375 对骨关节炎 (OA) 小鼠模型中软骨细胞代谢和氧化应激的影响。方法：软骨细胞分为对照、IL-1β、IL-1β+miR-375模拟物、IL-1β+miR-375抑制剂、IL-1β+miR-NC（阴性对照）和IL-1β+miR-375抑制剂 + siJAK2 组。MTT法检测软骨细胞增殖，相应试剂盒检测超氧化物歧化酶（SOD）和丙二醛（MDA）水平，TUNEL染色检测软骨细胞凋亡。此外，OA小鼠模型分为Sham组、OA+miR-NC组和OA+miRNA-375antagomir组。观察病理变化，分别通过qRT-PCR和Western blotting检测miR-375和JAK2/STAT3通路的表达。结果：与对照组相比，IL-1β 诱导的软骨细胞的 miR-375 和 MDA 显着增加，增殖和 SOD 水平降低。同时，它们还表现出细胞凋亡增加，ADAMTS-5 和 MMP-13 上调，COL2A1 和 ACAN 下调，以及 p-JAK2/JAK2、p-STAT3/STAT3 和 Bcl-2/Bax 降低。然而，这些变化在用 miR-375 抑制剂转染后显着改善，但用 miR-375 模拟物转染导致更严重的恶化。值得注意的是，转染 siJAK2 可以消除 miR-375 抑制剂的改善。此外，miR-375 antagomir 显着减轻了体内 OA 小鼠的 OA 进展。结论：