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Objective To investigate the preventive effect of Strontium ranelate on stress-absence induced osteoporo?sis in tail-suspended rat. Methods A total of 30 SD rats with average age of 6 month were randomly divided into 3 groups (n=10 in each group):Group A was normal control group while rats in group B and C were subjected to tail suspension test to establish stress absence models. Rats in group C were administered with Strontium ranelate [1 g/(kg·d)]. All rats were sacri?ficed 4 weeks later. Left femurs were harvested for bone mineral density (BMD) test and prepared for undecalcified tissue sec?tion and thereby bone histomorphometry assessment. Bone marrow from right femurs and tibias were cultured and induced to?wards osteogenic-differentiation. The expression levels of osteocalcin in the fourth-passage cultured bone marrow cells and in blood serum were detected separately. Results Rats in group B showed markedly decreased BMD comparing to those in group A and C(P<0.05). Trabecular volume (BV/TV), number (Tb.N) and thickness (Tb.Th) in group B were lower than those in group A and C;erosion percentage (Er.Pm) and osteoclast number (Oc.N) in group B and C were higher than those in group A;comparing to those in group B, bone formation rate (BFR/BV), labeled percentage (L.Pm), were higher in group C, coupled with decreased Er.Pm and Oc.N(P<0.05). mRNA expression levels of OCN in group B and C were higher than those of group A. But its level in plasma were lower in group B than those in group A and C(P<0.05). Conclusion Tail suspension could induce osteosporosis. Strontium ranelate prevent bone loss in stress-absence osteoporosis in rat induced by tail-suspension for 4 weeks, which might be partially through upregulating the expression of OCN, thereby promoting bone formation.
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BACKGROUND:To date, rivaroxaban has been a clinical y common anticoagulant in China;however, effective prophylaxis for venous thrombosis is associated with a markedly higher incidence of perioperative hemorrhagic complications. Although it has been reported that aspirin effectively prevents deep vein thrombosis and pulmonary embolism, the use of aspirin as a routine drug for venous thrombosis after total knee arthroplasty is stil controversial. OBJECTIVE:To compare the efficacy and safety of aspirin and rivaroxaban for prevention of deep vein thrombosis after total knee arthroplasty. METHODS:Total y 324 patients with osteoarthritis who underwent primary unilateral total knee arthroplasty were randomly divided into three groups. Twelve hours after the surgery, three groups were given aspirin, rivaroxaban and low-molecular-weight heparin respectively. Al three groups were treated for 14 days, and al of the patients were fol owed for 4 weeks. RESULTS AND CONCLUSION:Compared with the low-molecular-weight heparin group, the incidence of deep vein thrombosis was lower (P0.05). The results confirmed that rivaroxaban has a positive anticoagulation effect but leads to increases in wound complications in patients;there are no differences in efficacy and safety between aspirin and low-molecular-weight heparin, so aspirin as part of a multimodal anticoagulation therapy after total knee arthroplasty has good clinical safety and efficacy.