Osteoarthritis (OA) is one of the most prevalent pain‑inducing and disabling diseases globally. Aging is a primary contributing factor to the progression of OA. Forkhead box protein O4 (FOXO4) is known to be involved in the cell cycle and apoptosis regulation. The aim of the present study was to investigate the association between FOXO4 expression and chondrocyte degeneration in rats. Chondrocytes were assigned to the control (4‑week‑old rats), natural degeneration (16‑week‑old rats) or induced degeneration (IL‑1β‑treated chondrocytes from 4‑week‑old rats) groups. Immunocytochemical analysis with β‑galactosidase staining revealed a greater number of stained cells present in the natural and induced degeneration groups than in the control group. PCR analysis indicated lower mRNA expression levels of collagen type II α1 chain (Col2α) and higher levels of FOXO4, and western blotting revealed reduced Col2α protein expression levels and significantly elevated FOXO4 levels in the natural and induced degeneration groups, compared with those in the control group. The results of the present study revealed that FOXO4 expression was altered in the natural and induced degeneration groups, and further research and exploration are needed to clarify the underlying mechanism.

中文翻译：

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白细胞介素-Iβ通过调节叉头盒蛋白O4和Ⅱ型胶原促进软骨退变。

骨关节炎 (OA) 是全球最常见的引起疼痛和致残的疾病之一。衰老是 OA 进展的主要因素。已知叉头盒蛋白 O4 (FOXO4) 参与细胞周期和细胞凋亡调节。本研究的目的是研究 FOXO4 表达与大鼠软骨细胞变性之间的关系。软骨细胞被分配到对照组（4 周龄大鼠）、自然退化（16 周龄大鼠）或诱导退化（4 周龄大鼠经 IL-1β 处理的软骨细胞）组。用 β-半乳糖苷酶染色进行的免疫细胞化学分析显示，与对照组相比，自然和诱导变性组中存在更多数量的染色细胞。PCR 分析表明，与对照组相比，II 型胶原α1 链 (Col2α) 的 mRNA 表达水平较低，FOXO4 水平较高，蛋白质印迹显示自然和诱导变性组中 Col2α 蛋白表达水平降低，FOXO4 水平显着升高团体。本研究结果表明 FOXO4 在自然和诱导变性组中的表达发生了改变，需要进一步的研究和探索来阐明其潜在的机制。