缺血再灌注损伤后大鼠神经功能改变及大脑Homer1蛋白的表达

Neurological impairment and expression of Homer 1 protein in rats brain with ischemia-reperfusion injury

目的:观察大鼠局灶缺血再灌注(I/R)后神经功能的改变及脑内Homer1a、Homer1b/c蛋白的表达变化。方法:雄性SD大鼠120只,随机分为正常组(N组),假手术组(S组)及I/R组,每组40只,I/R组用大脑中动脉栓塞制作模型;S组仅行手术操作,不行线栓栓塞;N组正常饲养作为空白对照。分别在损伤后6、12、24、48及72 h采用神经损伤严重度评分(NSS)法对3组大鼠神经功能进行评估,取再灌注后0、1 h及上述时间点大鼠额顶叶皮层、海马裂解匀浆行Western blotting,对Homer1a及Homer1b/c蛋白行免疫印迹分析。结果:NSS显示I/R组大鼠在再灌注后6 h神经功能损伤最为明显(与同组其他时间点比较,P<0.001),然后逐渐恢复,72 h时接近术前水平(与N、S组比较,P<0.05)。Western blotting结果显示,I/R组神经组织中Homer1a蛋白的表达自伤后0 h起持续至伤后72 h,而正常及假手术组未见该蛋白阳性表达;Homer1b/c在3组均可见持续表达。结论:大鼠I/R损伤后Homer1a蛋白的表达于损伤前后有显著变化而Homer1b/c则无,结合NSS提示Homer1a蛋白可能参与脑I/R引起的神经功能损伤过程。

Objective： To observe the neurological changes and expression of protein Homerl a and Homerl b/c in rat brain with ischemia-reperfusion insult. Methods： 120 male SD rats were randomly divided into 3 groups of 40 each ： normal group （ N ）, sham group （ S ） and ischemia- reperfusion group （ I/R ）. The model of I/R was established by middle carotis arterial occlusion （MCAO） in I/R group. Operation procedures of the S group was the same as the I/R except for not conducting occlusion with nylon lines. Rats in N group was bred normally without any treatment. According to the observation time point, the scores of neurological deficits were evaluated at 6,12, 24,4g ,72 h after operation respectively among the 3 groups. Then the levels of Homerla protein expression in the frontal cortex, parietal lobe and hippocampus were measured by Western blotting at 0, 1,6, 12,24,48 and 72 h after operation. Results： The scores of NSS showed that the neurological impairment in I/R group（ 12.56 ± 1.24） was most serious at 6 h after I/R compared with other time points in the same group （ P 〈 0. 001 ） , and then decreased gradually to the lowest （2. 44 ± 0. 72, compared with group N and S, P 〈 0. 05） at 72 h after reperfusion. Homerl a was positive in I/R group from 0 h to 72 h after injury but no Homerl a was observed in normal group and sham group by Western blotting analysis. Homerl b/c were persistently expressed in the normal, sham and I/R groups. Conclusion： There is a significant change in Homerla expression before and after I/R insult, but no significant changes in Homerlb/c. These changes may be correlated with the neurological impairment.