Experimental Study Of Pravastatin On Early Stage Of Steroid-induced Avascular Necrosis Of The Femoral Head

Objective: To investigate the effect of pravastatin on early stage of steroid-induced avascular necrosis of the femoral head. Methods: 54 New Zealand white rabbits were randomly and equally divided into normal control group(Group A), model group(Group B)and treatment group(Group C). All rabbits in Group B and Group C were received 10ug/kg of lipopolysaccharide (LPS) intravenously twice at an interval of 24 hours. After the second injection of LPS, 20mg/kg methyprednisolone were injected for three consecutive days. Animals in Group C were treated with pravastatin at the 5th week, and the same volume of distilled water were given in Group A and Group B. All rabbits plasma lipid were measured with the blood from the marginal vein of auricle after 4, 8, 12 and 16 weeks. Six rabbits in each group were killed at the 8th, 12th and 16th week respectively, and femoral head specimens were analyzed by gross, histologic, electromicroscopic, immunohistochemical and in situ hybridization studies. The mRNA expression of vascular endothelial growth factor (VEGF) and core binding factor alpha 1 (Cbfa1) were detected by quantitative real-time PCR. Results: Compared with Group A, the level of cholesterol (CHOL) and triglyceride (TG) of Group B were significantly higher (P<0. 05) while the level of high-density lipoprotein(HDL)were lower (P<0. 05). At the 5th week, levels of CHOL and TG in Group A were significantly higher but the level of HDL were lower those of Group C.With the prolongation of the treatment of pravastatin, those three parameters appeared to normal station, and there were no significant differences between Group A and Group C. At the 8th week, the level of CHOL and TG in Group C were decreased but the level of HDL was increased. There were obviously differences of these three parameters between Group B and Group C after 12 weeks(P<0. 05). Compared with Group B, the histopathyology structure showed that the area of necrosis of Group C was decreased and the density of bone trabecular were increased. In Group C, both of the empty lacuna and fatty cell were decreased in the medullary cavity at the same time, and the mRNA expression of VEGF and Cbfal were significantly elevated than those of...