脊髓损伤早期及制动后大鼠股骨远端骨量丢失的实验研究

An experimental study of bone loss after spinal cord injury and immobilization in rats

目的:建立大鼠脊髓损伤及后肢废用模型,观察建模早期两种模型大鼠股骨远端骨密度及远端破骨细胞数量的改变。方法:24只SD大鼠随机分为3组(每组8只),对照组(A组),行T10椎板切除,不损伤硬膜及脊髓;脊髓损伤(SCI)组(B组):切除T10椎板后用Allen′s法(60g.cm势能)造成脊髓损伤;制动组(C组):采用大鼠双侧腿-尾缝合,造成双下肢制动。分别于造模后第1、7天采用BBB(Basso,Beattie and Bresnahan)评分评估脊髓损伤大鼠后肢运动功能,确定模型建立成功。建模第10天后处死,取一侧尺、桡骨及股骨远端,行骨密度检测。取另一侧股骨远端行TRAP染色,观察大鼠股骨远端破骨细胞数量的变化。结果:A、B、C 3组股骨远端骨密度值分别为0.114、0.096、0.108g/cm2,B组骨密度值最低,其次为C组,A组最高(P<0.05)。尺、桡骨骨密度3组比较无差异(P>0.05)。与A组比较,B组大鼠股骨干骺端破骨细胞数量增加显著,其次为C组,A组最少(P<0.01)。结论:脊髓损伤后,股骨远端破骨细胞数量大量增多,活性增强,骨吸收加强,引起脊髓损伤平面以下肢体骨量的迅速丢失,比废用性骨量丢失的程度更重。

Objective：To establish rats models with both spinal cord injury（SCI） and lower limbs disused atrophy,and to observe the bone density and number of osteoclast at distal femur.Method：A total of 24 male rats of 7 weeks were randomly divided into three groups：control group（group A）,the SCI group（group B） and the immobilization group（group C）.After general anesthesia,T10 vertebrae laminar was removed in group B and A,while weight-drop（60g·cm） on spinal cords（Allen′s contusion SCI model） was introduced only in group B;rats in group C were immobilized by bilateral hindlimbs-tail fixation.The Basso,Beattie,Bresnahan（BBB） scale was used to evaluate the injury severity by rating hindlimb functional deficits on day 1 and 7 post-injury.Animals were sacrificed on day 10 post-injury for subsequent analyses.Bone density of elbow-bone,radius and femur at one side was measured.The TRAP staining was performed on the distal femur of the other side to detect the number of osteoclast.Result：Bone density in the distal femur of group A,B,C was 0.114,0.096,0.108g/cm2.The difference of them was significant（P0.05）.No difference of bone density in the elbow-bone and radius between three groups was noted（P0.05）.Compared with group A,the number of osteoclast at the distal femora in group B increased most,the less was in group C and A（P0.01） respectively.Conclusion：SCI results in a rapid bone loss in early stage which is originated from increasing number and potential of osteoclast,which is more serious than disused bone loss.