Objective: To investigate the effect and mechanism of psoralen on calvarial osteoblasts injuries caused by tricalcium phosphate (TCP) wear particles in vitro.Methods: Primary osteoblasts were obtained from the calvaria of neonatal SD rat by the series of digestion and were identified with ALP staining. Calvarial osteoblasts were treated with TCP wear particles for 48 h to establish the in vitro model of osteoblasts injuries. The rat osteoblasts were randomly divided into control group, TCP wear particles (0.1 mg/ml) group, psoralen treated (at the concentrations of 10-7, 10-6, 10-5 mol/L) groups. WST assay and the flow cytometry were used to detect the cell viability of osteoblasts and apoptosis, respectively. Chemical colorimetry was performed to examine ALP activity of osteobalsts. When the osteoblasts were treated for 14 day, mineral nodules formation was observed with alizarin red S staining. Western blot was applied to examine protein expressions of glucose regulated protein78/94(GRP78/94), inositol dependent enzyme 1 alpha (IREα), spliced X-box binding protein 1 (XBP1s) and phosphorylated c-Jun N-terminal kinase (p-JNK) in calvarial osteoblasts. Results: Compared with control group, the cell viability of osteoblasts, ALP activity and mineral nodules formation in TCP group were decreased significantly (P＜0.05), while the percentage of apoptosis and protein expressions of GRP78/94, IRE1α, XBP1 and p-JNK were obviously increased in calvarial osteoblasts (P＜0.05). Compared with TCP group, the injuries of calvarial osteoblasts and cell apoptosis in psoralen treated groups were obviously decreased (P＜0.05), and the expression levels of GRP78/94, IRE1α, XBP1 and p-JNK were down-regulated remarkably (P＜0.05). Conclusion: Psoralen prevents osteoblasts injuries caused by TCP wear particles through IRE1α-XBP1s-JNK signaling pathway activation.
目的: 探讨补骨脂素(psoralen)对TCP磨损颗粒诱导成骨细胞损伤的影响及其分子机制。方法: 通过消化法从SD大鼠乳鼠颅骨中获取原代的成骨细胞,应用碱性磷酸酶(ALP)染色鉴定成骨细胞。TCP磨损颗粒(0.1 mg/ml)与成骨细胞共孵育48 h构建成骨细胞损伤的体外实验模型,实验随机分为正常对照组(Control)、模型(TCP)组和psoralen(10-7 mol/L、10-6 mol/L和10-5 mol/L)组。WST法和流式细胞术分别检测各组成骨细胞活性变化和凋亡情况;化学比色法检测成骨细胞中ALP活性;各组成骨细胞培养14 d后应用茜素红S染色观察矿化结节形成。Western blot法检测各组成骨细胞中葡萄糖调节蛋白78/94(GRP78/94)、肌醇依赖酶1α(IRE1α)、剪切型X盒结合蛋白1(XBP1s)和磷酸化c-Jun氨基末端激酶(p-JNK)等蛋白质的表达。结果: 与Control组比较,TCP组成骨细胞活性、ALP活性和矿化结节的生成显著降低(P＜0.05),细胞凋亡率、GRP78/94、IRE1α、XBP1s和p-JNK等蛋白质表达明显增加(P＜0.05);与TCP组比较,补骨脂素各组成骨细胞损伤情况明显减轻,细胞凋亡率显著减少(P＜0.05),GRP78/94、IRE1α、XBP1s和p-JNK等蛋白质表达也明显下降(P＜0.05)。结论: 补骨脂素可抑制TCP磨损颗粒诱导的IRE1α-XBP1s-JNK信号通路的激活,阻止TCP颗粒所致的成骨细胞损伤及凋亡。.
Keywords: ER stress; TCP wear particles; apoptosis; osteoblasts; psoralen; rat.