The Experiment Of Simvastatin Curing The Femoral Head Necrosis Due To Corticosteroid In The Early Stage

Objective: To research the effect of simvastatin on curing Rats，femoral head necrosisdue to corticosteroid in the early stage,through the elementary experiment ofsteroid-induced femoral necrosis animal models to explore its mechanism.Methods:A total of55Rats were randomly divided into normal control group (n=15)and experimental group (n=40). The experimental group was injected withDexamethasone Sodium Phosphate (20mg/kg) into gluteus maximus once a week tomake Rats，steroid-induced femoral head necrosis model in the early stage. At thesixth week,30out of40Rats were equally divided into model group and simvastatintherapy group. The therapy group was intragastrically administrated with simvastatin(10mg/kg) once a day. Model and control groups were intragastrically administratedwith the equal volume of saline. The femoral was obtained at4,8, and12weeks andthe the femoral head was analysed with the bone mineral density and observed withgeneral observation and light microscope.Results:○1After6weeks the model group X-ray shows the uneven density of thefemoral head and the bone morphology is not clear.The HE staining showed that thetrabecular bone atrophy, thinning, discontinuity of the bone marrow tissue steatosis,increased empty lacunae. The blank group were no abnormal changes.○2After12weeks of treatment, the bone mineral density in the therapy group was significantlyhigher than the model group, the difference was statistically significant (P<0.01).○3 Gross observation and light microscopy in therapy group demonstrated that thefemoral head was in good shape,the colour and luster of it was gradually gettingnormal;The bone trabecula increased thickly in many regions and the structure wasnearly regular;A large quantity of newborn bone-tissue and lots of newbornmicrovessels could been found around the necrosis regions and the shape of marrowcavity showed almost normal appearance.○4After12weeks of treatment, thepercentage of empty osteocyte lacunae was obviously lower in the therapy group thanthose in the model group,the difference was statistically significant (P<0.05).Conclusion: The unreasonable use corticosteroid can cause the femoral headnecrosis.Simvastatin could effectively restore steroid-induced femoral head necrosisin the early stage by several ways,such as to adjust the blood fats which impedepathological change, promote osteosis,increase bone density,repair the microstructureof bone tissue, improve the function of circulating endothelial progenitor cell,promoteregeneration of the blood vessel and so on.