Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China.
Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.
Toxicol Lett. 2018 Oct 1;295:229-236. doi: 10.1016/j.toxlet.2018.06.1221. Epub 2018 Jun 30.
Our previous in vivo studies showed that prenatal caffeine exposure (PCE) could restrain the development of chondrogenesis, which may delay fetal articular cartilage development and increase susceptibility to osteoarthritis in adults. So, the goal of the current study is to clarify theincreasing susceptibility to adult osteoarthritis in caffeine-exposed female offspring and its'mechanism. Pregnant rats were treated with 120 mg/kg·d caffeine or equal volumes of saline from gestational day (GD) 9 to 20. knee joints were collected from GD20 female fetuses and 18-week old female offspring which was treated with strenuous running for 6 weeks (55 min/day at 20 m/min) load to induce osteoarthritis. Knee joints from GD20 fetuses and adult offspring were collected for histochemistry and immunohistochemistry. Next, chondrocytes were isolated from 1-day-old newborn rats and in vitro studies were conducted where the cells in primary culture were exposed to 1, 10, and 100 μM caffeine and 250, 500, and 1,250 nM corticosterone. Insulin-like growth factor 1 (IGF-1) signal pathway genes' expression levels in fetal chondrocytes were studied, and IGF-1 histone acetylation was detected in vitro. Immunohistochemical results showed low expression levels of IGF-1 signaling genes (IGF-1, IRS-1, AKT, and COL2A1) both in fetal and adult cartilage with PCE. For adult offspring, histological results and Mankin score revealed increased cartilage destruction and accelerated osteoarthritis progression in PCE group with strenuous running exercise. Analysis in vitro revealed that caffeine and corticosterone impeded the expression of IGF-1 signaling pathway aggrecan and COL2A1 genes, but only corticosterone decreased H3K9 and H3K27 acetylation in the IGF-1 promoter region. In concluson, PCE low functional programmed cartilage IGF-1 by histone acetylation modification via overexposure to corticosterone and delayed articular cartilage development from fetus to adults. Then, the delayed cartilage development increased susceptibility to osteoarthritis in offsprings.
我们之前的体内研究表明，产前咖啡因暴露（PCE）可能会抑制软骨生成的发育，从而可能延迟胎儿关节软骨的发育，并增加成年后患骨关节炎的易感性。因此，本研究的目的是阐明咖啡因暴露的雌性后代易患成年骨关节炎及其“机制。从妊娠第 9 天到第 20 天，给怀孕的大鼠用 120mg/kg·d 咖啡因或等量的生理盐水处理。从妊娠第 20 天的雌性胎儿和 18 周龄的雌性后代中采集膝关节，这些后代经过 6 周的剧烈跑步（20m/min 时 55min/天）负荷诱导骨关节炎。从妊娠第 20 天的胎儿和成年后代中采集膝关节进行组织化学和免疫组织化学分析。接下来，从 1 日龄新生大鼠中分离出软骨细胞，并进行体外研究，其中原代培养的细胞暴露于 1、10 和 100μM 咖啡因以及 250、500 和 1250nM 皮质酮。研究了胎儿软骨细胞中胰岛素样生长因子 1（IGF-1）信号通路基因的表达水平，并在体外检测了 IGF-1 组蛋白乙酰化。免疫组织化学结果显示，PCE 下胎儿和成年软骨中的 IGF-1 信号基因（IGF-1、IRS-1、AKT 和 COL2A1）表达水平较低。对于成年后代，组织学结果和 Mankin 评分显示，在剧烈跑步运动的 PCE 组中，软骨破坏增加，骨关节炎进展加速。体外分析表明，咖啡因和皮质酮抑制 IGF-1 信号通路聚糖和 COL2A1 基因的表达，但只有皮质酮降低了 IGF-1 启动子区域的 H3K9 和 H3K27 乙酰化。总之，PCE 通过过度暴露于皮质酮导致组蛋白乙酰化修饰，使软骨 IGF-1 的功能编程降低，从而使胎儿到成年的关节软骨发育延迟。然后，软骨发育迟缓增加了后代患骨关节炎的易感性。
