大鼠脊髓钝挫伤后早期糖原合成酶激酶3β的表达及意义

Expression and Meaning of Glycogen Synthase Kinase 3β at Early Stage after Blunt Trauma in Spinal Cord of the Rat

目的研究大鼠脊髓钝挫损伤早期,脊髓损伤区域糖原合成酶激酶3-β(GSK3-β)的表达变化及细胞定位情况,探讨其在脊髓损伤(SCC)早期的生物学功能。方法将40只成年Sprague-Dawley(SD)大鼠随机分成假手术(Sham)组与SCC-12h、1d、3d和7d组,每组各8只。除Sham组大鼠外均采用改良Allen's法建立大鼠T10节段脊髓钝挫伤模型,用BBB评分评价各组大鼠的运动功能;采用荧光定量PCR(Q-PCR)及免疫组织化学法检测各组大鼠脊髓GSK3-β的表达情况,观察并统计不同时间点SCC组大鼠GSK3-β免疫组化阳性细胞的分布及数量变化。结果与Sham组相比,各SCC组大鼠BBB评分显著下降,术后第7d比第3d有所升高,差异有统计学意义(P<0.01)。GSK3-βmRNA相对表达量于术后12h明显降低,至术后第3d再次降低。免疫组织化学检测各SCC组GSK3-β阳性细胞均比Sham组少,差异有统计学意义(P<0.01),以SCC-3d组最少;脊髓灰质的GSK3-β阳性细胞主要在前角表达,其数量在SCC-12h组明显降低,术后第3d达到最低值,术后第7d明显升高,但仍然低于Sham组,差异有统计学意义(P<0.05);脊髓后角GSK3-β阳性细胞表达较少,各组间比较差异无统计学意义(P>0.05)。结论在维护脊髓正常功能中发挥重要作用;脊髓损伤后,机体通过调节GSK3-β的表达减轻炎症反应和促进损伤脊髓运动功能的恢复。

Objective To explore the expression and cellular localization of glycogen synthase kinase 3-beta（GSK3-beta） at early stage after blunt trauma in spinal cord of the rat and its biological functions at early stage in thespinal cord injury（SCC）.Method40 adult Sprague-Dawley（SD） rats were randomly divided into sham operation, SCC-12 h, SCC-1 d, SCC-3 d and SCC-7 group （8 rats in each group）. The blunt trauma model of spinal cord at T10 segment were established by improved Allen＇s method on rats from SCC groups besides the Sham group and Basso Beattie Bresnahan functional scale were used to evaluate the motor function of each group;the fluorescent quantitative PCR（Q-PCR） and immunohistochemistry were used to test the expression of GSK3-beta in the spinal cord and the distribution and quantity change of GSK3-beta positive cells by immunohistochemistry of rats from different SCC groups were observed and recorded. Results Compared with Sham group, BBB scores of rats in each SCC group decreased signifi- cantly, and the score on the 7th day was higher than that on the 3rd day, statistically significant（ P 〈 0. 01 ）. The relative expression of GSK3-β mRNA decreased significantly at 12h after operation and decre-ased again on the 3rd day after operation. The number of GSK3-β positive cells in each SCC group was lower than that in Sham group by immunohistochemistry（ P 〈 0. 01 ）, and the lowest was in SCC-3d group. The GSK3-β positive cells in gray substance spinal cord mainly expressed in the anterior horn, and the number of GSK3-β positive cells decreased significantly in SCC-12h group, being lowest at the third day after operation, increasing obviously at 7 day after operation, but it was still lower than that in sham group, statistically significant （P 〈 0. 05 ） ;The GSK3-β positive cells ex- pressed less in the spinal cord posterior horn, with no significant difference between the groups （ P 〉 0. 05 ）. Conclusion GSK3-βplays an important role in maintaining the normal function of the spinal cord. The body can reduce the inflammatory reaction and pro- mote the recovery of motor function of spinal cord by regulating the expression of GSK3-β after spinal cord injury.