Objective: To investigate the possibility of mitochondria-dependent apoptosis as a mechanism of early steroid-induced avascular necrosis of femoral head (SANFH) in rats and vitamin E as a possible prevention strategy.
Methods: Seventy-two male Sprague Dawley rats were randomly divided into control group, model group, and intervention group, with 24 rats in each group. The rats in control group were not treated as normal control. The rats in model group and intervention group were established early SANFH models by lipopolysaccharide combined with methylprednisolone injection. At the same time, the rats in intervention group were injected with vitamin E (40 mg/kg) every day for 7 days. At 2, 4, and 8 weeks after the final injection, the bilateral femoral heads were harvested and observed by HE staining, TUNEL assay, immunohistochemical staining, and Western blot. The rate of empty lacunae, apoptotic index, and the expressions of Caspase-9, Caspase-3, and cytochrome-c (Cyt-c) proteins were calculated.
Results: According to histological staining, there were significant differences in the rate of empty lacunae between intervention group and control group at 8 weeks ( P<0.05) and between intervention group and model group at 4 and 8 weeks ( P<0.05). The apoptotic index of intervention group was significantly lower than that of model group at each time point ( P<0.05). And there was significant difference between the intervention group and the control group at 8 weeks ( P<0.05). According to immunohistochemistry staining and Western blot, the expressions of Cyt-c, Caspase-9, and Caspase-3 all significantly decreased in intervention group than those in model group at each time point ( P<0.05); and the differences were significant between intervention group and control group at 8 weeks ( P<0.05).
Conclusion: Vitamin E can delay the progression of early SANFH by reducing mitochondrial dependent osteocyte apoptosis.
目的: 探讨维生素 E 防治大鼠早期激素性股骨头缺血性坏死（steroid-induced avascular necrosis of femoral head，SANFH）的可能性及作用机制。.
方法: 取雄性 SD 大鼠 72 只，随机分为对照组、模型组和干预组，每组 24 只。对照组大鼠不作处理；模型组及干预组采用脂多糖联合激素法制备 SANFH 模型，干预组在注射激素的同时每天肌肉注射维生素 E 40 mg/kg，连续 7 d。末次激素注射后 2、4、8 周取股骨头，HE 染色观察骨坏死发生情况，计算空骨陷窝率；TUNEL 染色观察细胞凋亡情况，计算细胞凋亡指数；免疫组织化学染色及 Western blot 检测观察胱天蛋白酶 9（Caspase-9）、Caspase-3、细胞色素-c（cytochrome-c，Cyt-c）蛋白表达情况。.
结果: 组织学观察示，干预组空骨陷窝率仅 8 周时与对照组比较差异有统计学意义（ P<0.05），4、8 周时与模型组比较差异有统计学意义（ P<0.05）；干预组细胞凋亡指数各时间点均低于模型组（ P<0.05），8 周时与对照组比较差异有统计学意义（ P<0.05）。免疫组织化学染色及 Western blot 观察示，干预组各时间点 Cyt-c、Caspase-9、Caspase-3 蛋白表达显著低于模型组（ P<0.05），8 周时与对照组相比差异有统计学意义（ P<0.05）。.
结论: 维生素 E 可通过减轻线粒体依赖性骨细胞凋亡来延缓大鼠早期 SANFH 病程发展。.
Keywords: Steroid-induced avascular necrosis of femoral head; apoptosis; rats; vitamin E.