Toll样受体4在兔激素性股骨头坏死中的表达及意义

Expression and Significance of toll-like receptor 4 in the avascular necrosis of the femoral head in rabbit Induced by a combination of methylprednisolone and lipopolysaccharide(LPS)

目的:应用激素联合脂多糖诱导早期兔股骨头缺血性坏死,探讨Toll样受体4在股骨头坏死发生中的介导作用。方法:健康雄性SD大鼠40只随机分为实验组20只和对照组20只。实验组连续两天静脉注射脂多糖(大肠杆菌内毒素)2mg/kg,第天3,4和5天再连续肌肉注射甲强龙20mg/kg;对照组同样方法注射生理盐水。最后一次甲强龙注射1,2,3或4周后处死动物,每周进行血清中IL-1α,IL-β,IL-2,IL-10,GM-CSF,IFN-a,TNF-y细胞因子分析;生化分析血清甘油三酯、总胆固醇水平;常规HE染色行组织病理学检测;应用免疫组织化学检测各组股骨头组织中在不同时间点TLR4的表达。结果:与对照组相比,ANFH模型组血清甘油三酯血清第1周开始升高,第2和3周显着下降;血清总胆固醇浓度在第1、2周显着增加,但第4周显着下降;与对照组相比,实验组第1、2周血清中各种前炎症细胞因子明显增高;免疫组化结果分析,与对照组相比,实验组股骨头组织中TLR4阳性表达率显著增高。结论:脂多糖及甲强龙诱导的大鼠股骨头坏死可能与破坏先天免疫系统功能,成骨合成及质代谢有关。这些结果表明TLR4的信号转导通路在股骨头缺血性坏死发病过程中起重要的促进作用。

Objective To explore the role of toll-like receptor 4 in the pathogenesis during the course of avascular necrosis of the femoral head in rabbit Induced by a combination of methylprednisolone and lipopolysaccharide（LPS）.Methods 40 healthy male Wistar rats were randomly divided into experimental group（20） and control group（20）.Experimental group were intravenously injected the lipopolysaccharide 2 mg/kg on the first and second day and then continuously were given 20mg/kg methylprednisolone intramuscularly on the other three days by ;The control group received normal saline by the same way.The animals were sacrificed 1,2,3 or 4 weeks after the last methylprednisolone injection and The serum level of cytokines of IL-1α,IL-β,IL-2,IL-10,GM-CSF,IFN-a,TNF-y were measured Weekly;Biochemical analysis of serum triglycerides,total cholesterol were also performed weekly;The sevrity of osteonecrosis was evaluated histologically;The detection of TLR4 in the femoral head was investigated by the methods of immunohistochemistry.Results Compared with control group,in the ANFH group serum levels of triglyceride increased by week1,then decreased significantly weeks2 and 3;The serum total cholesterol concentrations significant increase by week 1、2 but then decreased significantly by week 4.In Serum level of preinflammatory cytokines ofIL-1α,IL-β,IL-2,IL-10,GM-CSF,IFN-a,were increased by week1and 2;The results of immunohistochemistry analysis shows,compared with the control group,the expression of TLR4 in the femoral head was significantly increased in the experimental group.Conclusion LPS and methylprednisolone induced osteonecrosis of the femoral head in rats and this was associated with a disruption of the innate immune system,osteogenesis and lipid synthesis.These findings suggest that the TLR4 signalling pathway plays an important role in the pathogenesis of femoral head osteonecrosis.