Effect Of Lithium Chloride On Bone Metabolism Of Steroid-induced Femoral Head Necrosis In Rats And Its Mechanism

Object:To study the effect of lithium chloride on bone metabolism in steroid-induced osteonecrosis of the femoral head(S-ONFH)in Rats and its mechanism.Methods:30 SD rats were randomly divided into blank control group,steroid group and lithium chloride group,with 10 rats in each group.Lithium chloride and steroid group by escherichia coli endotoxin in combination with large dose of steroid shock made rat model of the S-ONFH,After the last injection of steroid 24 h,Lithium chloride group was given lithium chloride(140mg / kg)by gavage,1 times / day for 8 weeks.The steroid group and the blank group were given equal amount of normal saline.Rats were sacrificed and the left femoral head was used for micro CT examination,and each bone mineral density(BMD),bone volume fraction(BV/TV),trabecular space(Tb.Sp),trabecular bone number(Tb.N),trabecular bone thickness(Tb.Th)were recorded;The right femoral head was stained with HE to observe the pathological changes and necrosis of femoral head;TRAP staining and ALP staining were used to measure the number of osteoblasts and osteoclasts,the changes of bone metabolism in the femoral head were observed at the cellular level;Immunohistochemical staining was used to detect the expression of ?-catenin,OPG and RANKL in femoral head,semi-quantitative analysis of the differences in protein expression in each group,at the molecular level to explore the role of lithium chloride in the local bone metabolism of the mechanism of bone.Results:MicroCT analysis shows: Compared with the blank control group,the BMD,BV / TV,Tb.N and Tb.Th of the steroid group and the lithium chloride group were all decreased,while those of Tb.Sp increased,but these in the steroid group expressed more significantly(all P <0.05).HE staining shows: Comparison of two groups is P < 0.05.HE staining showed that the trabecular bone in the blank group was complete and arranged,and the bone lacunae were filled with bone cells;the trabecular bone in steroid group was disorder,narrow,and fractured,and marked necrosis of bone widely exists in empty bone lacunae;the trabecular bone shape in lithium chloride group,is better,no obvious stenosis or fracture.However,there are empty bone lacuna in lithium chloride group which is less than that in steroid group,0%,80% and 30% rats with femoral head necrosis were in blank control group,steroid group and lithium chloride group,respectively;Osteogenesis and osteoclast count results: Compared with the blank control group,the number of osteocytes in the steroid group and the lithium chloride group decreased,but the steroid group decreased more significantly(all P <0.05),compared with the blank control group,the number of osteoclasts in the steroid group and the lithium chloride group increased,but the steroid group increased more significantly(all P <0.05);Immunohistochemical results showed: The expression of ?-catenin and OPG in blank control group was higher than that in steroid group and lithium chloride group,the lithium chloride group was higher than the steroid group(all P <0.05);The expression intensity of RANKL in blank control group was lower than that in steroid group and lithium chloride group,Lithium chloride group was lower than the steroid group(all P <0.05).Conclusions:The model of steroid-induced osteonecrosis of the femoral head was successfully prepared by the combination of Escherichia coli endotoxin and high-dose hormone;lithium chloride can improve the femoral head ultrastructure and bone strength,promote osteoblast proliferation,differentiation,and enhance bone tissue osteogenic metabolism,While inhibiting osteoclast proliferation,differentiation and bone resorption,delay bone loss,Inhibition of bone;Lithium chloride may promote the proliferation of ?-catenin,up-regulation of classical Wnt signaling pathway function,promote osteoblast-associated factor OPG expression,while inhibiting osteoclast-related factor RANKL expression levels,Affect the OPG / RANKL system,May be one of the important mechanisms of its treatment of teroid-induced osteonecrosis of the femoral head.