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目的：通过研究homer1a 基因敲除小鼠脑缺血再灌注损伤及海马区星形胶质细胞活化、数目形态变化，探讨homer1a 基因在脑缺血损伤中的作用及机制。方法：取雄性homer1a 基因敲除（Knock Out，KO）小鼠及同窝野生型（Wild Type，WT）小鼠各15 只，分为基因敲除假手术组（ShamKnock Out，SKO，n=3）、基因敲除型缺血2 h 再灌注24 h 组（Model Knock Out，MKO，n=12）、野生型假手术组（ShamWild Type，SWT，n=3）及野生型缺血2 h 再灌24h 组（ModelWild Type，MWT，n=12）。线栓法闭塞小鼠大脑中动脉制作脑缺血再灌注损伤模型（middle cerebral artery occlusion and reperfusion , MCAO/R），在缺血再灌注损伤前（0 h）及缺血再灌注后3 h、6 h、12 h、24 h后进行改良版神经损伤严重性评分（modified Neurological severity scores，mNSS）、2，3，5—氯化三苯基四氮唑(2,3,5triphenyltetrazoliumchloride, TTC )染色、苏木素—伊红染色（Hematoxylin-eosin staining，HE）、原位末端转移酶标记技术（terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling，TUNEL）检测及免疫荧光染色观察海马区星形胶质细胞神经纤维酸性蛋白（Glial Fibrillary Acidic Protein，GFAP）改变。结果：SKO组、SWT 组行为学 mNSS 评分均为0 分，TTC 染色未见梗死灶。TUNLE 及GFAP染色阳性细胞数很少且未见统计学差异（P>0.05）。脑缺血再灌注 24 h后，MKO 组mNSS 评分较MWT 组高；TTC染色MKO 组较MWT 组梗死百分比高；MKO组较MWT 组TUNEL凋亡率高； GFAP免疫荧光染色阳性数MKO组少于MWT 组，且均有统计学差异(P<0.05)。结论：homer1a 基因敲除加重了小鼠脑缺血再灌注损伤，星形胶质细胞可能参与并发挥复杂作用。

英文摘要:

Objective:To investigate effect of homer1a and observe Astrocyte activation in hippocampus through homer1a gene knockout (KO) mice with focal cerebral ischemia-reperfusion insult.Methods:15 male homer1a gene KO mice and 15 male wild-type (WT) mice were randomly divided into four groups. sham operated group (SKO, n=3; SWT, n=3); model groups (MKO, n=12; MWT, n=12). Mice were subjected to transient middle cerebral artery occlusion (MCAO) for 2 h, followed by 24 h reperfusion with model group. Sham group were subjected to the same surgical procedure without MCAO. The neurological function was evaluated with the modified neurological severity scores (mNSS) at 0 h, 3 h, 6 h, 12 h, 24 h. after MCAO/R. It was marked 0 h before MCAO operation; Brain slices were observed for infarction by 2,3,5 triphenyltetrazolium chloride(TTC); Histomorphology of brain slices were observed by HE-staining; The cell apoptosis were determined by using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL); and the specific markers glial fibrillary acidic protein(GFAP) of astrocyte(Ast) was measured by immunofluorescence.Results:It was almost 0 score point that mNSS scores of mice in SKO group and SWT group; No ischemic lesion was found in SKO group and SWT group; There was not significant differences in rations of tunel-positive cells, number of GFAP-positive cells between SKO group and SWT group. (P>0.05) The mNSS score raised in the MKO group versus those in the MWT group at 24 h point (P<0.05); TTC staining showed increased infarct volume in MKO group compared with MWT group (P<0.05); The percentage of TUNEL-positive cells was higher in MKO group than MWT group (P<0.05); But,the expression of GFAP was declined in MKO group than MWT group (P<0.05).Conclusion:Homer1a KO mice exacerbated focal cerebral ischemia reperfusion injury and Ast maybe paly a role via homer1a in this process.

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