降钙素治疗骨折的疗效观察及机制探讨

目的观察降钙素治疗骨折的疗效，并探讨其机制。方法选用64只2个月龄SD雌性大鼠，行双侧卵巢切除（OVX）后建立骨质疏松性骨折动物模型，随机分为观察组、对照组，各32只。观察组从骨折术前1周至术后8周每天皮下注射鲑鱼降钙素2IU／kg，对照组注射等量生理盐水。采用原位杂交技术检测7、14、28、56d骨痂中Ⅰ、Ⅱ、Ⅲ型胶原mRNA的表达。结果从骨折后第7天开始至第56天，各组Ⅲ型胶原mRNA表达水平逐渐下降，Ⅱ型胶原mRNA表达水平先升高后下降，Ⅰ型胶原mRNA表达水平逐渐升高。从第28天起，Ⅰ型胶原mRNA表达水平观察组〉对照组（P均〈0．05）。术后第56天观察组骨痂已为骨性，对照组可见较多软骨性骨痂。结论降钙索能促进软骨性骨痂向骨性骨痂转换，加速骨质疏松性骨折的愈合。其机制可能与降钙素能促进Ⅰ型胶原mRNA表达，抑制Ⅱ型胶原mRNA表达有关。

Effect and mechanism of calcitonin on osteoporosic fracture healing in rats

Objective To observe the effect of calcitonin on fracture healing proces, and explore the mechanism. Methods 64 female two months SD rats were under two-side ovariectomy（OVX） and divided randomly into observation group and control group. The rats in observation group were treated with calcitonin by subcutaneous injections（2 IU/kg ） every day from 1 week pre-operation to 8 weeks post-opertion. Calluses were collected at the end of 7,14,28 ,and 56 days postoperatively. The expression of type Ⅰ , Ⅱ ,Ⅲ collagen mRNA of cancellous bone was detected by in situ hybridization localization. Results The expression of type Ⅲ collagen mRNA in all groups gradually decreased,though that of 1 collagen mRNA gradually increased, the expression of type Ⅱ collagen mRNA levels increased first and then decreased from 7 days to 56 days postoperatively. From the first 28 days, the expression of matrix type Ⅰ collagen mRNA was increased signif icantly than that of the control group （ P 〈 0.05 ）. Observation group had bony callus and in the control group is still mostly cartilaginous at the end of 56 days postoperatively. Conclusion Calcitonin may improve the process of the osteoporotic fracture healing through promoting the expression of type Ⅰ collagen mRNA and inhibiting expression of type Ⅱ collagen mRNA.