The Metabonomic Study Of Epimedium On Improving Glucocorticoid-induced Osteoporosis

Objective: Glucocorticoids are widely used to treat inflammatory and many immune-mediated diseases in clinical practice.However,glucocorticoid-induced osteoporosis(GIO)is the most common type of secondary osteoporosis,which was just next to the incidence of the post-menopausal osteoporosis and senile osteoporosis.It has been proved that the long-term use of glucocorticoids lead to the disorder of glucose,lipid,protein and water salt metabolism.Epimedium is a commonly used traditional Chinese medicine for the prevention and treatment of osteoporosis in clinic.But it is not clear about the overall metabolic characteristics of GIO,and there has not been reported regarding the metabolic regulation of Epimedium in treatment of osteoporosis.Therefore,this study aimed to analyse the metabolic characteristics of GIO model rats by using a 1H NMR-based metabonomic approach in conjunction with multivariate data analysis,and elucidate metabolic changes and regulation of metabolic pathway of Epimedium in the treatment of GIO through the comparative analysis,which will provide a scientific basis for the clinical application of Epimedium in improving GIO.Methods: The 40 male SD rats were randomly assigned to four groups.All groups were subjected to subcutaneous injections of dexamethasone(0.1 mg/kg/day)for 5 weeks,while the control group received the same volume of saline.At the same time,Epimedium rats were gavaged with extract of Epimedium at a dose of 10 g/kg/day and the positive drug group was gavaged with Alendronate(1.2 mg/kg/day)for 5 weeks.Simultaneously,the control and GIO rats received distilled water(10 g/kg/day).The serum and urine samples were collected at the end of weeks 0,3 and 5.Femurs and kidney were removed from each animal at the end of the 5th week.The serum,urine,bone marrow and kidney samples were used for metabolite determination.Simultaneously,femurs were used for bone mineral density(BMD)analysis and serum samples also were analysed for the levels of alkaline phosphatase(ALP)and carboxy-terminal telopeptide of type I collagen(CTX).Results: After 5 weeks of subcutaneous injection of dexamethasone,the BMD of rats was significantly decreased,the level of ALP in serum was significantly decreased,and the content of CTX was markedly increased,which indicated the GIO model was successfully established.Compared with the GIO model group,the rats in the Epimedium treatment group showed significantly increased levels of BMD,which demonstrated that treatment with Epimedium had an effect on alleviating GIO.A significant increase in ALP was found and the level of CTX was reduced in the Epimedium treatment group,which suggested that Epimedium increased bone mass by improving bone metabolism.Through the metabonomic study,we found that Epimedium reversed the metabolic changes in the body fluid and tissue of GIO model rats and the metabolic characteristics was closed to normal group,which showed that Epimedium can regulate the metabolism disorder of GIO model rats from the overall.(1)Epimedium treatment can reduce the levels of lactate and lipid in the serum,but up-regultae the levels of creatine/creatinine,PC/GPC,taurine,glycine,β-glucose and alanine.(2)Epimedium treatment can decrease the urinary phenylacetylglycine in model rats,as well as increase the levels of 2-oxoglutarate,citrate,succinate,PC/GPC,creatine/creatinine,taurine and hippurate,and make them tend to normal levels.(3)As for bone marrow samples,Epimedium can inhibit the increase of lactate and 3-hydroxybutyrate,up-regulate the levels of leucine,alanine,acetate,creatine,choline,taurine and glycine.(4)Epimedium treatment can decrease the levels of lactate and glutamate and increase the levels of choline,taurine,alanine and glycine in kidney samples.Conclusion: In this study,the BMD and clinical biochemistry assessments demonstrated that Epimedium treatment can significantly improve the GIO.1H NMR metabonomics study suggested that Epimedium can regulate the metabolic disorder of GIO by regulating energy metabolism,glucose and lipid metabolism,fatty acid oxidation,amino acid metabolism,phospholipid metabolism,choline metabolism and intestinal flora metabolism to reveal the metabolic regulation effects of Epimedium in improving GIO,providing a scientific basis for clinical application of Epimedium in the prevetion and treatment of GIO.