MMP-2、12在兔脊髓损伤中的表达及与损伤程度的相关性研究

目的观察兔损伤段脊髓内MMP-2、12的表达及与损伤程度、损伤后时间点的相关性。方法将135只兔随机分为全瘫组(A组)、不全瘫组(B组)和假手术对照组(C组),每组45只。A、B组采用Allen打击法建立不同程度脊髓损伤模型,C组仅行椎板切除术。分别于致伤后6h、24h、48h、7d和14d采用免疫组织化学染色法检测兔脊髓组织中MMP-2表达,实时荧光定量PCR法检测兔脊髓组织中MMP-12的表达;运用改良Tarlov评分评价术前1h,术后麻醉清醒后6h,损伤后24h、48h、7d、14d兔后肢运动功能。结果(1)三组在各时间点均有MMP-2、12表达,但同一时间点A、B组与C组比较,差异有统计学意义(P0.05);伤后24h、48h、7dA组的表达高于B组,差异具有统计学意义(P0.05),C组各时间点表达均维持在较恒定水平。脊髓损伤后6hMMP-2、12表达增加,伤后24h达高峰,直至7d仍有MMP-2、12的高表达。(2)各时间点兔后肢运动功能评分C组明显高于A、B组,A组同时间点评分低于B组,差异具有统计学意义(P0.05);A、B组不同时间点MMP-2阳性细胞表达率和MMP-12实时荧光定量CT值与兔Tarlov评分的相关系数分别为r=-0.887,P=0.000和r=-0.841,P=0.002。结论兔脊髓损伤后MMP-2、12的表达明显升高,且与脊髓损伤程度呈负相关。

Studies on the expression of MMP-2,MMP-12 and the correlation with degree of injury after spinal cord injury in rabbits

Objective To observe the expression of MMP-2,MMP-12 and the correlation with degree of injury after spinal cord injury in rabbits.Methods One hundred and thirth-five rabbits were randomly divided into 3 groups：complete paraplegia group （A group）,incomplete paraplegia （B group） and sham-operation control group （C group）.Models of spinal cord injury in different degrees were established by Allen method in group A and B.Animals in C group were only performed laminectomy.Posttraumatic myeloid tissues were achieved at 6 h,24 h,48 h and 7 d,14 d after spinal cord injury in rabbits.The expression of MMP-2 with immunohistochemistry,the expression of MMP-12 with fluorescent quantitation PCR and the Tarlov scales of hindlimb movement were measured in three groups respectively.Results 1.At all time points,expression of MMP-2 and MMP-12 were found in three groups.At the same time point,expression of MMP-2 and MMP-12 in group A and group B were significantly higher compared with group C （P〈0.05）.Also,those in group A were significantly higher compared with group B at 24 h,48 h and 7 d after spinal cord injury （P〈0.05）.Relatively constant levels of expression of MMP-2,MMP-12 were maintained in group C over time.The expression of MMP-2,MMP-12 were all increased in group A and group B at 6 h,the activities of MMP-2,MMP-12 reached the maximum level at 24 h and MMP-2 persisted in this level to 7 d after spinal cord injuries.2.Tarlov scales of hindlimb movement in group C were significantly higher compared with group A and group B,and there was statistical difference between those in group A and group B （P〈0.05）.Correlation coefficients between expression rate of MMP-2 positive cells,real-time fluorescence of MMP-12 CT values and Tarlov scores at different time points in group A,B were as follows：r=-0.841,P=0.002;r=-0.887,P=0.000.Conclusions The results show that MMP-2,MMP-12 are highly expressed in the spinal cord after spinal cord injuries in rabbits.The expression level changes of MMP-2,MMP-12 negatively correlate with injury degree of spinal cord.