Study On Mechanical Properties Of Osteoporosis Treated With BMSCs Transplantation

Background:Osteoporosis(OP)is a systemic metabolic bone disease characterized by decreased bone mass,bone tissue microstructure damage,resulting in increased bone brittleness and prone to fracture.Recent studies have shown that homing and senescence of bone marrow mesenchymal stem cells(BMSCs)are the main causes.In this study,osteoporosis may lead to the deficiency of BMSCs,the decrease of osteogenic ability and the imbalance of cellular bone formation,which may change the shear and impact mechanical properties and biological indexes of animal bone.After the intervention of BMSCs,the shear and impact mechanical properties and biological indexes of osteoporotic model animals may be restored to a certain extent.Objectives:The purpose of this study is to study the therapeutic effect of BMSCs transplantation on osteoporotic rats in cytology and biomechanics,and compare it with the existing clinical drug therapy,to explore whether the cell-based replacement therapy based on BMSCs can become an effective method of OP therapy in the future.Methods:88 6-month-old female SD rats were randomly divided into normal control group and osteoporotic animal model group.The osteoporotic animal model was treated with raloxifene.Osteoporosis animal model bone marrow mesenchymal stem cells intervention group(n = 22).The animal model of osteoporosis was established by ovariectomy in rats.After 4 weeks of feeding,osteoporotic animal models were treated with bone marrow mesenchymal stem cells and raloxifene respectively.After6 weeks of treatment,the serum levels of estradiol(E2),estradiol receptor(ER),superoxide dismutase(SOD),malondialdehyde(MDA)and calcium(Ca)were measured.the serum phosphorus(P),alkaline phosphatase(ALP),and evaluate the changes of osteoporosis related factors after treatment.Then the humerus of each group was scanned to analyze its bone mineral density(BMD),the tibia was taken for shear test,and the femur was taken for impact test to verify the improvement of bone in osteoporotic rats after treatment.Finally,the proximal metaphysis of femur of rats in each group was stained with histological HE to analyze the improvement of trabeculae at the site of osteoporosis.Results:The values of serum E2,ER,SOD,BMD,Ca,ALP and histological HE staining of bone marrow mesenchymal stem cells in the intervention group were higher than those in the model group and raloxifene group,and the values of serum P and MDA in the raloxifene group were significantly lower than those in the model group and raloxifene group.Conclusions:After using BMSCs transplantation to treat osteoporotic animals,the serum E2,ER,SOD,BMD,Ca and ALP indexes of osteoporotic rats were recovered to some extent,trabeculae and bone mineral density were significantly increased,and the shear and impact mechanical properties of bone were recovered to a certain extent,which significantly improved the bone at the site of osteoporosis.And its therapeutic effect is significantly better than that of clinical medication.This study provides a new theoretical basis for the future treatment of osteoporosis through the use of stem cell BMSCs for cell-based replacement therapy.