摘要
目的:观察病变侧亚低温对大鼠局灶性脑缺血再灌注后生长抑制和DNA损伤诱导基因45(Gadd45)和Bcl-2蛋白变化的影响。方法:实验于2004-11/2005-07在哈尔滨医科大学病理教研室实验室完成。将雄性Wistar大鼠48只随机分为4组:①常温缺血组(n=20):采用改良线栓法建立大鼠大脑中动脉缺血2h再灌注模型,再灌3,12,24,48和72h分别处死,每个时间点4只。②亚低温缺血组(n=20):造模和处死时间同常温缺血组,并于栓塞后30min实施病灶侧亚低温(设定制冷器温度为6～8℃,脑内缺血区温度为32℃左右)并持续4h。③假手术组(n=4):手术,但不栓塞,术后24h处死。④正常组(n=4):不干预。各组大鼠处死前进行神经功能缺陷评分(0～4分,评分越高,神经功能缺陷越重);苏木精-伊红染色观察组织病理变化;采用免疫组化的方法检测Gadd45和Bcl-2蛋白的表达。结果:48只进入结果分析。①神经功能缺陷评分:亚低温缺血组大鼠各时间点均明显低于常温缺血组(P<0.05)。②Gadd45表达:在再灌注3h表达增强,且随再灌注时间的延长而逐渐增强(P<0.05),至48h达高峰,其后又随之下降。亚低温缺血组各时间点表达明显少于常温缺血组(P<0.05)。③Bcl-2表达:再灌注3h增多,随再灌注时间的延长,其表达逐渐增多(P<0.05),至24h达高峰,其后又随之下降,亚低温缺血组各时间点表达明显高于常温缺血组(P<0.05)。结论:Gadd45在脑缺血再灌注损伤过程中,早期能修复受损的DNA,损伤加重时则促进细胞凋亡;Bcl-2在脑缺血再灌注损伤过程中主要起抑制细胞凋亡的作用。亚低温能减少Gadd45的表达,增加Bcl-2的表达;能明显减轻缺血所致的损伤,并能明显抑制细胞调亡;对大鼠缺血后神经功能的恢复有确切的疗效。
AIM： To observe the effect of local mild hypothermia on expression of Gadd45 and Bcl-2 protein after focal cerebral isehemia and repeffusion injury.
METHODS： The experiment was conducted at the laboratory of Staff Room of Pathology, Harbin Medical University from November 2004 to July 2005. A total of 48 male Wistar rats were assigned randomly into 4 groups： （1）normal ischemic group （n=20）： ischemic for 2 hours and repeffusion at middle eerebral artery models were established with modified thread emolism. After reperfusion for 3, 12, 24, 48 and 72 hours the rats were killed, respectively, 4 rats at each time point. （2）Sub-hypothermia ischemia group （n=20）： the establishment of models and the killing time were the same to that of the normal ischemic group. Sub-hypothermia at focal side was performed 30 minutes after embolism for 4 hours （equipment at 6-8 ℃, cerebral ischemic area at about 32 ℃. （3）Sham-operation group （n=4）： Operation was conducted, but no embolism, and the rats were killed at the 24^th hour after operation. （4）Normal group （n=4）： No intervention. Neural functional defect evaluation was conducted before death in each group （0-4 points, the higher the score, the more severe the neural runctional defect was）. Histological change a,d pathological change were observed with hematoxylin and eosin. The expressions of Gadd45 and Bcl-2 protein were detected with immunohistoehemical method,
RESULTS： A total of 48 rats were involved in the result analysis. （1）Assessment of neural functional defect： It was lower significant in the sub-hypothermia isehemie group at each time point than that in the normal ischemic group （ P 〈 0.05）. （2）Gadd45 expression： The expression increased at the 3^nl hour after reperfusion, and it increased gradually with the elongation of reperfusion time （ P 〈 0.05）. Till the 48^th hour it reached the peak, and then fell down. The expression in the sub-hypothermia ischemic group at each time point was less obviously than that in the normal ischemic group （P 〈 0.05）. （3）Bcl-2 expression： It increased at the 3^nl hour after reperfusion, and still increased gradually with the prolongation of reperfusion time （P 〈 0.05）. Till the 24^th hour it reached the peak, and then decreased. The expression in the sub-hypothermia ischemic group at each time point was higher markedly than that in the normal ischemie group （P 〈 0.05）.
CONCLUSION： Early days in ischemic/reperfusion, Gadd45 could repair the suffering DNA, it could promote apoptosis when damage aggravated. Bcl-2 couhl restrain apoptosis. Mild Hypothermia could reduce expression of Gadd45 and increase expression of Bcl-2, could markedly alleviate pathological change result from ischemia and prevent dramatically apoptosis and executed value curative effect for neurological comeback after rat suffer isehemic damage.
出处
《中国临床康复》
CAS
CSCD
北大核心
2006年第14期83-85,共3页
Chinese Journal of Clinical Rehabilitation
