脊髓损伤对大鼠骨转换及骨密度的影响

Influence of Spinal Cord Injury on Bone Turnover and Bone Mineral Density in Rats

目的 :探讨脊髓损伤 (spinalcordinjury ,SCI)对大鼠骨转换及骨密度的影响。方法 :6 0只 3月龄SD大鼠均分为SCI组与对照组。SCI组于T10 处完全横断脊髓 ;对照组仅行椎板切除术。术后 1、3、6周时处死动物测血清钙(Ca)、磷 (P)、碱性磷酸酶 (ALP)、尿钙、磷、肌酐 (Cr)以及胫骨、股骨骨密度 (bonemineraldensity ,BMD )。结果 :截瘫鼠血钙、尿钙、尿钙 /肌酐在伤后不同时间段均升高 ;血ALP在伤后 1周时显著下降 ,3、6周时恢复正常。胫骨近端 ,股骨远、近端的BMD在 6周时较对照组下降且差异显著。结论 :SCI大鼠可见明显的骨转换增高以及破骨活性增强 ,其生化、骨密度的改变与人体有较好的相关性。SD大鼠可用于评价SCI后骨代谢改变 。

Objective: To explore the influence of spinal cord injury on bone turnover and bone mineral density(BMD)in rats.Methods:Sixty SD rats,aging 3 months ,were diveded into SCI group and control group equally.Rats in the experimental group underwent spinal cord transection at the tenth thoracic vertebrae.Control rats underwent laminectomy without any spinal cord lesion.Rats in both groups were sacrificed at 1,3 ,6 weeks postoperatively,with 10 animals at every interval.Biochemical testing of the serum concentrations of ionized calcium,phosphorus,ALP,and urine concentrations of calcium,phosphorus,creatinine were performed at every interval and bone mineral density in femur and tibia were measured with dual energy X ray absorptiometry at 3 and 6 weeks after surgery.Results:Compared with control rats,rats with SCI had high level of serum ionized calcium,urinary calcium and urinary/creatinine at each interval.At 1 weeks,the significance decrease of serum ALP was found in rats with SCI,however,it returned to the normal level at 3 and 6 weeks.Decreased BMD was obviously detected in the proximal femur,distal femur and proximal tibia in rats with SCI at 6 weeks in comparison with the controls.Conclusions:High bone tureover and raised osteoclast activity were obviously seen in rats with SCI.Reductions in BMD in SCI rats at 6 weeks and changes in biochemical were similar to that reported in human with paraplegia.Thus,SD rats could be used to evaluate changes in bone metabolism following SCI,also,SD rats appear to be good osteoporosis animal models following SCI.