环维黄杨星D对高血压大鼠脑缺血GAP-43与Neurocan表达的影响

目的 观察中药单体环维黄杨星D(CVB-D)对易卒中型肾血管性高血压大鼠(RHRSP)脑缺血一复流不同时间脑组织生长相关蛋白43(GAP-43)与神经粘蛋白(Neurocan)表达的影响.方法 采用环形银夹使SD大鼠双侧肾动脉狭窄,制成RHRSP,再用线栓法制成一侧大脑中动脉闭塞(MCAO)模型.用免疫组化方法观察CVB-D对MCAO大鼠脑缺血2h后复流1、7、14、30d脑组织GAP-43与Neurocan表达的影响,并与生理盐水组对照.结果 缺血2h后再灌注1d,对照组缺血周围半暗区出现GAP-43阳性细胞,7d明显增多,14d减少,30d明显减少,各时间点阳性细胞数表达差异有显著性意义(P＜0.01);治疗组GAP-43阳性细胞数表达在各时间点较对照组显著增加(P＜0.01).Neuroean阳性细胞数表达对照组在缺血再灌注ld出现,7d明显增多,14d达高峰,30d时下降,但仍高于假手术组水平(P＜0.05);治疗组neurocan阳性细胞数表达在缺血再灌注7、14、30d则较对照组显著减少(P＜0.01).结论 CVB-D上调RHRSP脑缺血区GAP-43阳性细胞数表达与下调Neurocan表达的作用,可能是其促进脑损伤区中枢神经修复的重要机制之一.     

电针对脑缺血大鼠神经黏蛋白mRNA表达与细胞超微结构的影响

目的观察电针对易卒中型肾血管性高血压大鼠(stroke prone renovascular hypertensive rats,RHRSP)脑缺血-再灌注后不同时间点神经黏蛋白mRNA(neurocan-mRNA)表达、细胞超微结构的影响。方法用环形银夹使SD大鼠的双侧肾动脉狭窄,制成RHRSP,再用线栓法制成一侧大脑中动脉闭塞(middle cerebral artery occlu-sion,MCAO)模型。运用原位杂交和电镜等技术观察电针对脑缺血2h后再灌注1、7、14、30d大鼠脑内神经黏蛋白-mRNA表达与细胞超微结构的干预作用,并与对照组比较。结果电针组脑缺血-再灌注7、14、30d大鼠脑缺血区周围及海马区neurocan-mRNA表达均低于同期对照组,差异有统计学意义(P<0.05);电针组神经元、血管壁等细胞超微结构的损伤较对照各组减轻。结论电针对RHRSP脑缺血-再灌注损伤的保护作用,可能与其下调神经抑制因子neurocan-mRNA表达、减轻细胞超微结构损害等机制有关。     

环维黄杨星D对高血压大鼠脑缺血神经胶质原纤维酸性蛋白与神经粘蛋白表达的影响

目的 观察中药单体环维黄杨星D（CVB-D）对易卒中型肾血管性高血压大鼠（RHRSP）脑缺血再灌注不同时间神经胶质原纤维酸性蛋白（GFAP）与神经粘蛋白（neurocan）表达的影响。方法 100只SD大鼠随机分成随机分为空白组10只（不作任何处理的RHRSP）、假手术组10只（仅作手术创伤分离动脉，不结扎动脉）、CVB-D治疗组40只、生理盐水对照组40只。采用环形银夹使SD大鼠的双侧肾动脉狭窄，制成RHRSP，再用线栓法制成一侧大脑中动脉闭塞（MCAO）模型。用免疫组化等方法观察CVB-D对脑缺血2h后再灌注1、7、14、30d不同时间点大鼠脑组织GFAP与neurocan表达。结果 缺血2h再灌注后．治疗组脑缺血区周围GFAP阳性表达细胞呈现先递增后减少的趋势。与对照组相比，除第1天外，第7、14、30天差异都有显著性意义（P〈0．05）。Neurocan在空白组、假手术组未见阳性细胞，缺血再灌注1d对照组出现neurocan阳性表达细胞，并且呈先递增后减少趋势。治疗组neurocan阳性表达细胞与对照组相比．除第1天外，第7、14、30天差异都有显著性意义（P〈0．05）。结论 CVB-D有促进RHRSP脑缺血损伤区神经功能的修复作用，可能与其下调神经抑制因子GFAP、neurocan的表达等机制密切相关。     

运动训练对大鼠脑缺血再灌注后神经修复及GAP-43和Neurocan表达的影响

目的 观察运动训练对大鼠脑缺血再灌注后不同时间神经修复及GAP-43与Neurocan表达的影响.方法 健康雄性Wistar大鼠72只,随机分成运动训练组、对照组、假手术组.采用线栓法制作一侧大脑中动脉闭塞(MCAO)模型,以神经功能缺损评分和Morris水迷宫试验进行神经功能评价,免疫组化法观察对脑缺血周围GAP-43与Neuorcan的表达.结果 与对照组比较,脑缺血再灌注后14d、21d,运动组的肢体运动及记忆功能明显恢复;缺血再灌注后7d,对照组缺血周围出现GAP-43阳性细胞,14d减少,21d、28d明显减少,运动组GAP-43表达在14d、21d、28d较对照组显著增加(P<0.05).Neurocan阳性细胞在对照组缺血再灌注7d出现,14d达高峰,21d、28d时下降;运动组Neurocan表达在缺血再灌注14d、21d、28d较对照组显著减少(P<0.05).结论 运动训练上调大鼠脑缺血区GAP-43表达与下调Neurocan表达,可能是其促进脑损伤区中枢神经修复的重要机制之一.     

脑缺血再灌注损伤模型大鼠大脑皮质BDNF mRNA表达减少

目的制备局灶性脑缺血再灌注损伤大鼠模型,并观察大脑皮质脑源性神经营养因子(BDNF)mR-NA表达的变化。方法雄性SD大鼠,采用线栓法闭塞大脑中动脉2h后进行再灌注3d,制备局灶性脑缺血再灌注损伤模型。采用神经缺失评分观察大鼠的行为学表现;TTC染色检查脑组织梗死情况;HE染色观察大鼠脑组织形态结构;RT-PCR技术检测大鼠大脑皮质BDNF mRNA的表达。结果假手术组大鼠无神经功能障碍表现;脑组织未见梗死灶;脑组织神经细胞形态规则;大脑皮质BDNF mRNA的相对表达量,与正常组相比,未见明显变化。与假手术组相比,局灶性脑缺血再灌注损伤模型大鼠出现神经功能障碍;左侧半球可见梗死灶;梗死侧脑组织形态学观察显示神经细胞大量坏死脱落、胞质呈空泡变性、疏松、胞核浓缩深染;大脑皮质BDNF mRNA表达量明显减少。结论大脑中动脉闭塞2h后进行再灌注3d可造成脑缺血再灌注损伤,可能与大脑皮质BDNF mRNA的表达减少有关。     

头孢曲松钠对脑缺血再灌注大鼠脑损伤和谷氨酸转运体-1表达的影响

目的 研究头抱曲松钠对脑缺血再灌注损伤大鼠的神经损害程度、脑组织水肿以及谷氨酸转运体-1(GLT-1)表达的影响.方法 线栓法阻塞大鼠大脑中动脉,并于缺血后2h进行再灌注,造成脑缺血再灌注损伤,大鼠分为假手术组(S组)、脑缺血再灌注组(M组)、头孢曲松钠组(C组)3组,C组于造模后6h给予头孢曲松钠200mg/(kg·d),共5d.脑缺血再灌注ld、3d、5d时进行大鼠神经行为学评分和脑组织含水量测定,RT-PCR检测GLT-1 mRNA表达.结果 M组、C组较S组大鼠神经行为学评分降低,脑组织含水量增加,GLT-1 mRNA表达相对量减少;M组上述改变在缺血再灌注3d时最明显,5d时有所减轻.在同一实验时间点,C组较M组大鼠神经行为学评分明显升高,脑组织含水量明显减少,GLT-1 mRNA表达量明显增加(P<0.01),且C组GLT-1 mRNA表达相对量随时间延长逐渐增加(P<0.05).结论 脑缺血再灌注损伤中,头孢曲松钠可能通过上调GLT-1 mRNA的表达来减轻脑缺血损伤和再灌注后脑水肿,从而发挥神经保护作用.     

8溴-环磷酸腺苷对脑缺血再灌注大鼠PKA及GAP-43蛋白表达的影响

目的:观察脑室注射8-溴-环磷酸腺苷(8-B-cAMP)对脑缺血再灌注大鼠大脑皮质蛋白激酶A(PKA)及生长相关蛋白43(GAP-43)表达的影响。方法:采用线栓法制作大鼠脑缺血再灌注模型,将45只大鼠分为假手术对照组,缺血组(单纯脑缺血再灌注组)和8-B-cAMP组(脑缺血再灌注并脑室注射8-B-AMP)。用放免法测缺血周边区脑组织cAMP的含量,Westernblot(免疫印迹法)检测蛋白激酶A(PKA)及生长相关蛋白43(GAP-43)的表达。结果:脑缺血组6h、24h cAMP的含量下降,GAP-43及PKA蛋白表达减少;8-B-cAMP治疗组脑组织GAP-43蛋白表达较缺血组增加,且这种变化与cAMP的含量及PKA蛋白表达增加相一致。结论:8-B-AMP能够增加PKA及GAP-43的表达从而促进脑缺血再灌注后的轴突再生。     

丁苯酞预处理对脑缺血再灌注大鼠内质网应激的影响

目的 探讨丁苯酞预处理对脑缺血再灌注大鼠内质网应激的影响.方法 30只SD大鼠随机分成假手术组、缺血再灌注组、丁苯酞预处理组,每组10只大鼠.丁苯酞预处理组大鼠给予丁苯酞80 mg/kg灌胃,1次/d;缺血再灌注组和假手术组大鼠给予等量生理盐水替代.灌胃7d后,采用Zea Longa法制备大鼠脑缺血再灌注模型.假手术组不插入线栓.采用TTC染色检测脑梗死面积;RT-PCR法测定脑组织葡萄糖调控蛋白78(GRP78) mRNA、C/EBP同源蛋白(CHOP) mRNA的表达.结果 假手术组大鼠脑组织未见梗死灶;丁苯酞预处理组大鼠脑梗死面积明显小于缺血再灌注组(P＜0.05).缺血再灌注组和丁苯酞预处理组大鼠脑组织GRP78 mRNA、CHOP mRNA的表达量明显高于假手术组(均P＜0.05);丁苯酞预处理组大鼠脑组织GRP78 mRNA、CHOP mRNA的表达量明显低于缺血再灌注组(均P＜0.05).结论 丁苯酞可能通过抑制内质网应激而起到脑保护作用.     

大鼠脑缺血再灌注后海马CA1区星形胶质细胞与突触可塑性的关系

目的 研究大鼠脑组织缺血再灌注后星形胶质细胞与GAP-43变化的关系.方法 建立局灶性脑缺血再灌注模型.72只大鼠随机分为假手术组、缺血再灌注组,在各时间点处死取脑,应用免疫组化法检测海马CA1区GFAP、GAP-43的表达.结果 不同时间点缺血再灌注组GFAP、GAP-43表达均高于同时期假手术组(P＜0.01);缺血再灌注组GFAP与GAP-43高度相关(P＜0.05).结论 脑缺血再灌注后,海马CA1区星形胶质细胞与GAP-43变化具有高度相关性.     

大鼠局灶性脑缺血再灌注损伤后GAP-43及IGF-1促进神经元再生表达的实验研究

目的探讨Wistar大鼠脑缺血再灌注损伤后生长相关蛋白GAP-43抑制神经元凋亡和胰岛素样生长因子-I(IGF-1),促进神经元再生的可塑性表达机制。方法将80只成年健康雄性Wistar大鼠,分为GAP-43组和IGF-1组,每组各40只,并随机分为正常对照组、假手术组和缺血1h再灌注2h、6h、12h、24h、48h、3d、7d、14d组,每组4只(n=4)。应用线栓法制备大鼠脑缺血再灌注动物模型,并采用免疫组织化学方法检测GAP-43与IGF-1在神经元凋亡中的表达情况,并进行图像分析。结果GAP-43组:缺血再灌注2h,海马、皮质区及纹状体区神经元GAP-43呈基础表达,6~48h表达逐渐增高,7d达高峰,14d达最低,P<005。与假手术组比较有显著性差异,P<005。IGF-1组:正常对照组及假手术组在海马区、皮质区及纹状体区IGF-1阳性标记出芽细胞呈基础表达。缺血再灌2hIGF-1表达明显增高,24h达高峰,P<0.05。48h恒定表达。3~14d仍维持高值表达,P<0.05。结论GAP-43与IGF-1参与抑制并促进神经元轴突再生的表达。     

大鼠脑缺血再灌注损伤后GAP-43及IGF-1在神经系统中的表达

目的探讨大鼠脑缺血再灌注损伤后生长相关蛋白-43（GAP-43）和胰岛素样生长因子-1（IGF-1）的表达。方法成年健康雄性Wistar大鼠72只，随机分为GAP-43组36只和IGF-1组36只，每组再分为假手术组和缺血1h再灌注2h、6h、12h、24h、48h、3d、7d、14d组，每组4只（n=4）。应用线栓法制备大鼠脑缺血再灌注动物模型，免疫组织化学方法检测GAP-43与IGF-1在神经元中的表达。结果GAP-43组：缺血再灌注2h，皮质区、海马及纹状体区神经元GAP-43呈基础表达，6h后表达逐渐增高，7d达高峰，14d开始降低，较假手术组高（P〈0．05）。IGF-1组：缺血再灌2h IGF-1表达明显增高，24h达高峰，48h恒定表达，14d仍维持高表达，较假手术组高（P〈0．05）。结论GAP-43和IGF-1可能参与促进神经元轴突的再生。     

脑缺血再灌注损伤后GAP-43蛋白的表达和意义

目的 探讨脑缺血再灌注损伤后生长相关蛋白-43（GAP-43）的表达对神经元轴突再生的可塑性变化.方法 成年健康雄性Wistar大鼠40只,随机分为正常对照组、假手术组和缺血1h再灌注2h、6h、12h、24h、48h、3d、7d、14d组,每组各4只（n=4）.应用线栓法制备大鼠脑中动脉闭塞再灌注模型（MCAO）,采用免疫组织化学方法检测GAP-43的表达并观察神经元轴突再生的变化,并进行计算机图像分析.结果 缺血再灌注2h,海马、皮质区及纹状体区GAP-43呈基础表达,6h、12h、24h、48h表达逐渐增高,7d达高峰,P＜0.05,14d达最低表达,P＜0.05.与假手术组比较有显著性差异,P＜0.05.正常对照组无表达.缺血再灌注48h～7d损伤区域神经元轴突呈出芽征,发出突触纤维.结论 脑缺血再灌注损伤后GAP-43呈非特异性表达,并促进神经元的修复和再生.     

神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用

目的探讨神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用。方法采用线栓法制作缺血再灌注大鼠模型,分别用神经节苷脂(治疗组)和生理盐水(对照组)腹腔注射。观察两组大鼠缺血90min、缺血90min再灌注24h的脑梗死面积、神经功能缺损程度、细胞凋亡数、细胞凋亡率。结果治疗组大鼠于相同时间点脑梗死面积较对照组明显减小,仅表现轻度的神经功能缺损,且神经细胞的凋亡数较对照组显著减少(均P<0.01)。结论神经节苷脂能明显减小大鼠实验性脑缺血的脑梗死面积,减轻脑缺血再灌注后神经功能缺损程度,显著减轻缺血区神经元损害,具有显著的脑保护作用。     

Hyperlipidemia affects neuronal nitric oxide synthase expression in brains of focal cerebral ischemia rat model★

BACKGROUND: Hyperlipidemia, a risk factor for ischemic cerebrovascular disease, may mediate production of neuronal nitric oxide synthase (nNOS) to induce increased nitric oxide levels, resulting in brain neuronal injury. OBJECTIVE: To investigate effects of hyperlipidemia on brain nNOS expression, and to verify changes in infarct volume and pathology during reperfusion, as well as neuronal injury following ischemia/reperfusion in a rat model of focal cerebral ischemia. DESIGN, TIME AND SETTING: Complete, randomized grouping experiment was performed at the Laboratory of Physiology, Shanxi Medical University from March 2005 to March 2006. MATERIALS: A total of 144 eight-week-old, male, Wistar rats, weighing 160-180 g, were selected. A rat model of middle cerebral artery occlusion was established by suture method after 4 weeks of formulated diet. Nitric oxide kit and rabbit anti-rat nNOS kit were respectively purchased from Nanjing Jiancheng Bioengineering Institute, China and Wuhan Boster Biological Technology, Ltd., China. METHODS: The rats were equally and randomly divided into high-fat diet and a normal diet groups. Rats in the high-fat diet group were fed a high-fat diet, consisting of 10% egg yolk powder, 5% pork fat, and 0.5% pig bile salt combined with standard chow to create hyperlipidemia. Rats in the normal diet group were fed a standard rat chow. A total of 72 rats in both groups were randomly divided into 6 subgroups: sham-operated, 4-hour ischemia, 4-hour ischemia/2-hour reperfusion, 4-hour ischemia/4-hour reperfusion, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion, with 12 rats in each subgroup. MAIN OUTCOME MEASURES: nNOS expression was measured by immunohistochemistry, and pathomorphology changes were detected by hematoxylin-eosin staining. Infarct volume and nitric oxide levels were respectively measured using 2, 3, 5-triphenyltetrazolium chloride (TTC) and immunohistochemistry. RESULTS: In the ischemic region, pathology changes were significant in the 4-hour ischemia/4-hour, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion subgroups fed on a high-fat diet compared to the same groups fed on a normal diet. In each ischemia subgroup, nNOS expression in brain tissues was higher than in the sham-operated subgroups fed on either the high-fat diet or normal diet (P < 0.01). At each ischemia/reperfusion time point, rats fed on a high-fat diet expressed higher levels of nNOS compared to rats fed on the normal diet (P < 0.05). When tissue was stained with TTC, a white infarction area was detected in the ischemic hemisphere, demonstrating that the infarct volume gradually increased with prolonged reperfusion time in each ischemia subgroup. At each ischemia/reperfusion time point, the infarct volume was larger in rats fed on a high-fat diet compared to those fed on a normal diet. CONCLUSION: nNOS expression was greater in hyperlipidemia rats following ischemia/reperfusion. Cerebral ischemia/reperfusion injury is aggravated with prolonged reperfusion time. Key Words: focal cerebral ischemia; hyperlipidemia; ischemia/reperfusion injury; neuronal nitric oxide synthase     

Hyperlipidemia affects neuronal nitric oxide synthase expression in brains of focal cerebral ischemia rat model★

BACKGROUND: Hyperlipidemia, a risk factor for ischemic cerebrovascular disease, may mediate production of neuronal nitric oxide synthase (nNOS) to induce increased nitric oxide levels, resulting in brain neuronal injury. OBJECTIVE: To investigate effects of hyperlipidemia on brain nNOS expression, and to verify changes in infarct volume and pathology during reperfusion, as well as neuronal injury following ischemia/reperfusion in a rat model of focal cerebral ischemia. DESIGN, TIME AND SETTING: Complete, randomized grouping experiment was performed at the Laboratory of Physiology, Shanxi Medical University from March 2005 to March 2006. MATERIALS: A total of 144 eight-week-old, male, Wistar rats, weighing 160-180 g, were selected. A rat model of middle cerebral artery occlusion was established by suture method after 4 weeks of formulated diet. Nitric oxide kit and rabbit anti-rat nNOS kit were respectively purchased from Nanjing Jiancheng Bioengineering Institute, China and Wuhan Boster Biological Technology, Ltd., China. METHODS: The rats were equally and randomly divided into high-fat diet and a normal diet groups. Rats in the high-fat diet group were fed a high-fat diet, consisting of 10% egg yolk powder, 5% pork fat, and 0.5% pig bile salt combined with standard chow to create hyperlipidemia. Rats in the normal diet group were fed a standard rat chow. A total of 72 rats in both groups were randomly divided into 6 subgroups: sham-operated, 4-hour ischemia, 4-hour ischemia/2-hour reperfusion, 4-hour ischemia/4-hour reperfusion, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion, with 12 rats in each subgroup. MAIN OUTCOME MEASURES: nNOS expression was measured by immunohistochemistry, and pathomorphology changes were detected by hematoxylin-eosin staining. Infarct volume and nitric oxide levels were respectively measured using 2, 3, 5-triphenyltetrazolium chloride (TTC) and immunohistochemistry. RESULTS: In the ischemic region, pathology changes were significant in the 4-hour ischemia/4-hour, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion subgroups fed on a high-fat diet compared to the same groups fed on a normal diet. In each ischemia subgroup, nNOS expression in brain tissues was higher than in the sham-operated subgroups fed on either the high-fat diet or normal diet (P< 0.01). At each ischemia/reperfusion time point, rats fed on a high-fat diet expressed higher levels of nNOS compared to rats fed on the normal diet (P<0.05). When tissue was stained with TTC, a white infarction area was detected in the ischemic hemisphere, demonstrating that the infarct volume gradually increased with prolonged reperfusion time in each ischemia subgroup. At each ischemia/reperfusion time point, the infarct volume was larger in rats fed on a high-fat diet compared to those fed on a normal diet. CONCLUSION: nNOS expression was greater in hyperlipidemia rats following ischemia/reperfusion. Cerebral ischemia/reperfusion injury is aggravated with prolonged reperfusion time.     

Reversible focal ischemic injury demonstrated by diffusion-weighted magnetic resonance imaging in rats.

BACKGROUND AND PURPOSE: Diffusion-weighted magnetic resonance imaging (DWI) can quantitatively display focal brain abnormalities within minutes after the onset of ischemia. We performed the present study to determine the effects of 1 and 2 hours of temporary ischemia on DWI. METHODS: We examined DWI and T2-weighted magnetic resonance images (T2WI) during and after 1 and 2 hours of temporary middle cerebral artery occlusion in rats (n = 10 for each group). In a subgroup of four animals from each group, we employed perfusion magnetic resonance imaging to monitor cerebral perfusion. Neurological outcome and infarct size after survival for 24 hours were compared between the groups and correlated with DWI and T2WI studies. RESULTS: Perfusion studies qualitatively documented hypoperfusion and reperfusion during and after temporary occlusion. Lesion size on DWI during reperfusion was significantly less than that during ischemia for 1 (55% decline, p less than 0.02) but not 2 hours of occlusion. The DWI signal intensity ratio (intensity compared with that in the contralateral homologous area) just before withdrawal of the occluder was significantly less in regions where the hyperintensity disappeared after withdrawal than in regions with persistent hyperintensity (p less than 0.002). The T2WI studies revealed few or no abnormalities, except after 2 hours of occlusion. The neurological outcome was significantly better in the 1-hour than in the 2-hour group (p less than 0.05). Postmortem infarct volume was significantly smaller in the 1-hour group than in the 2-hour group (p less than 0.05). The postwithdrawal DWI accurately predicted infarct size (R = 0.96, p less than 0.0001). CONCLUSIONS: The present study indicates that DWI can rapidly display not only irreversible but also reversible ischemic brain damage and enhances the importance of DWI as a diagnostic modality for stroke.     

大鼠大脑中动脉缺血/再灌注模型中Caspase-3的表达

目的 研究Caspase-3在缺血性脑损伤中的作用，进一步探讨缺血性脑血管病的分子机制。方法 用Belayev改良的Longa线栓法制备大鼠局灶性大脑中动脉(MCA)缺血／再灌注模型，TTC染色观察梗死灶的形成，分别用原位杂交及免疫组化技术检测鼠脑中Caspase-3 mRNA与活性蛋白的表达。结果 缺血2小时再灌注24小时，TTC染色见明显的梗死灶形成，正常脑组织、假手术组及MCAO缺血对侧脑中有少量的Caspase-3 mRNA表达，但活性蛋白几无表达；再灌注24小时后，缺血侧脑中Caspase-3 mRNA表达明显增强，蛋白质活化增多，再灌注48小时进一步增加。结论 细胞凋亡机制参与了缺血后迟发性神经元死亡，Caspase-3在其中起重要作用。     

大鼠脑缺血再灌注半暗带β淀粉样前蛋白mRNA表达与梗死体积的关系

为了探讨大鼠局灶性脑缺血再灌注缺血半暗带β淀粉样前蛋白(APP)转录水平与缺血时间及梗死体积的相互关系，用插线法建立大鼠局灶性脑缺血再灌注模型，剥取缺血半暗带皮质组织，采用半定量逆转录－聚合酶链式反应（RT－PCR），测定永久性缺血48h和不同缺血时间再灌注48h后，APPmRNA水平的变化。结果显示，梗死体积随再灌注前缺血时间的延长而增大，皮质半暗带缺血30min再灌注48h APPmRNA表达升高；缺血60min和缺血120min再灌注48h APPmRNA升高明显；缺血180min再灌注48h和永久性缺血48h APPmRNA达到高峰。提示缺血半暗带APPmRNA的表达随再灌注前缺血时间延长而增加并与梗死体积有一定的相关性，早期再灌注可减少其表达。（（GFDA1））。