ABSTRACT
OBJECTIVE:To compare the effects of strontium ranelate and PTH(1-34)on bone quality of ovariectomized rats. METHODS:80 SD rats were randomly divided into sham operation group(group A,n=10)and dual ovariectomy(group B,n=70). 3 months after operation,group B were randomly divided into 7 groups,with 10 rats in each group. B0 group were given nor-mal saline [0.9 g/(kg·d)] subcutaneously;B1-B3 groups were given low-dose,medium-dose and high-dose of strontium ranelate [0.45,0.9,1.35 g/(kg·d)] intragastrically;B4-B6 groups were given low-dose,medium-dose and high-dose of PTH(1-34)[30, 60,90 μg/(kg·d),treated for 5 days,rested for 2 days] subcutaneously. Group A was same to group B0 in therapy regimen. All rats were sacrificed 8 weeks later. The contents of P1NP and CTX-1 in serum of rats were determined by ELISA assay;bone densi-ty of 4th lumbar vertebrae was detected by bone densitometer;BV/TV,Tb.Th,Tb.N and Tb.Sp were detected by CT;maximal load and elastic modulus of 5th lumbar vertebrae were measured by compression test. RESULTS:Compared with group A,the se-rum levels of P1NP and CTX-1 in B0-B6 groups increased significantly,while bone density of 4th lumbar vertebrae,maximal load and elastic modulus of 5th lumbar vertebrae decreased significantly in B0-B3 groups(P0.05). CONCLUSIONS:PTH(1-34) is better than strontium ranelate in inhibiting bone loss,improving vertebral bone micro-structure and biomechanical properties of ovariectomized rats.
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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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Objective To investigate the effects of lovastatin alone or combined with calcitonin on fracture repair in osteoporotic rats. Methods Forty 4-month-old female SD rats were randomized into 5 groups(8 rats in each group):normal fractured group (A), osteoporotic fractured group (B), lovastatin treatment group(C), calcitonin treatment group (D) and lovastatin combined with calcitonin treatment group. All rats except group A received bilateral ovariectomy. The midshaft femur fracture model was established in all rats 8 weeks after operation. The serum level of procollagen amino-terminal propeptide (PINP) was assessed by ELISA. X-ray and bone mineral density detection was used to observe the fracture healing process. The maximal loading of femoral fractures was analyzed by biomechanical method. Results (1) The serum level of PINP was significantly lower in group A than that of other groups. There was a significantly higher level of PINP in group C and group E than that of group B, and the level of PINP was significantly lower in group D than that of group C. (2) The X-ray showed more progressed fracture healing in group A and group E. The accordingly score indicated that there was a markedly higher score in groups A and group E compared to that of other three groups. (3) There was a highest bone mineral density in the full-length and in the middle of femur bone in group A, followed by group E, group D and group C. The lowest bone mineral density was found in group B. (4) The biomechanical test showed that the maximal loading in femur fracture side was significantly higher in group A than that of other four groups, in which it was higher in group E than that of group B. Conclusion The osteoporosis decreased bone mass and delayed fracture healing process in rat model. The treatment of lovastatin combined with calcitonin showed more positive effect on preventing bone loss and promoting fracture repair than lovastatin alone.