Objective To study the protein expression levels of matrix metalloproteinases (MMPs)and their inhibitors in bone tissues of rat femoral head and to explore the relationship between necrosis of femoral head and glucocorticoid.Methods Twenty healthy adult SD rats were randomly divided into glucocorticoid group and control group,with 10 rats in each.Glucocorticoid group was treated with intramuscular injection of hydrocortisone twice a week.The control group received normal saline of the same volume.Four weeks later,bone tissues of left femoral head were collected from each group of rats for HE determination of femoral head necrosis.The expressions of matrix metalloproteinase-1 (MMP-1 ), matrix metalloproteinase-2 (MMP-2 ), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1 ),and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2 )at mRNA and protein levels were detected by RT-PCR and Western blot techniques,respectively.Results The expressions of MMP-1 and MMP-2 at mRNA and protein levels were higher in glucocorticoid group than those in the control group. However,TIMP-1 and TIMP-2 gene and protein expression levels were lower in glucocorticoid group (all P<0.05). Conclusion The expressions of MMPs in bone tissues of rat femoral head in early necrosis were increased,but their inhibitors had decreased expressions. We can draw the conclusion that glucocorticoid-induced necrosis of femoral head may be related to its regulation of the expression levels of MMPs and their related inhibitors.%目的 观察大鼠股骨头骨组织中基质金属蛋白酶(MMP s)及其抑制剂的表达变化,探索股骨头坏死形成与应用糖皮质激素之间的相互关系.方法 20只SD大鼠,雌雄各半,分为2组(n=10).激素模型组肌注醋酸氢化可的松,2次/周;对照组给予等量生理盐水.4周后,取各组大鼠左侧股骨头的骨组织进行HE染色确定股骨头坏死病变情况;采用RT-PCR及Western blot技术分别检测大鼠股骨头组织中MMP-1、MMP-2、MMPs组织抑制剂-1(TIMP-1)、TIMP-2的mRNA和蛋白表达变化.结果 激素模型组MMP-1、MMP-2 mRNA及蛋白表达较对照组升高,TIMP-1、TIMP-2的mRNA及蛋白表达降低(均为P<0.05).结论 股骨头坏死早期大鼠股骨头骨组织中MMPs表达升高,其相关抑制剂表达降低,推测糖皮质激素导致股骨头坏死可能与其对体内MMP s及其相关抑制剂的调控有关.
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