不同后处理措施对大鼠局灶性脑缺血-再灌注损伤的影响

目的探讨不同后处理措施对大鼠局灶性脑缺血-再灌注损伤的影响。方法成年SD大鼠96只,随机分为12组,每组均采用阻断右侧大脑中动脉90min,再灌注24h的方法制备局灶性脑缺血-再灌注损伤大鼠模型。本实验分为缺血后处理(IP)、纳洛酮后处理(N)、联合后处理(C)3部分。IP部分分为4组(每组n=8):对照组、IP-15s组、IP-30s组和IP-1min组,后3组在缺血90min后再灌注15s、30s、1min,缺血15s、30s、1min,反复3次。N部分分为4组(每组n=8):对照组、纳洛酮1mg/kg组(N1组)、5mg/kg组(N2组)、10mg/kg组(N3组)后处理组。再灌注即刻腹腔注射不同剂量纳洛酮或生理盐水(对照组)10mL。上述两部分于再灌注24h行神经功能缺损评分(NDS评分),后断头取脑,测定脑梗死面积百分比。C部分分为4组(每组n=8):C1为对照组、C2为缺血后处理最佳时间窗组、C3为纳洛酮后处理最佳剂量组,C4为C2和C3联合组。于再灌注24h断头取脑检测脑组织微管相关蛋白2(MAP2)的表达水平。结果 IP部分与对照组、IP-15s和IP-1min组相比,IP-30s组的NDS评分和缺血侧脑梗死面积百分比显著降低,(P<0.05);N部分与对照组、N1和N2组相比,N3组的NDS评分和缺血侧脑梗死面积百分比显著降低,(P<0.05);C部分与C1、C2、C3组相比,C4组缺血侧脑组织MAP2表达水平明显增加,(P<0.05)。结论在局灶性脑缺血-再灌注损伤大鼠,缺血后处理和纳洛酮后处理均可产生神经保护作用,并且联合应用这两种后处理措施可获得增强的神经保护作用。     

联合应用缺血后处理、远隔缺血后处理和纳洛酮后处理对大鼠脑缺血-再灌注损伤的影响

目的 评价联合应用缺血后处理、远隔缺血后处理和纳洛酮后处理对大鼠局灶性脑缺血-再灌注损伤的影响.方法 将110只大鼠随机分为5组(n=22),通过阻塞右侧大脑中动脉90 min和再灌注24 h实施局灶性脑缺血.再灌注.Ⅰ组为对照组;Ⅱ组为缺血后处理组,再灌注开始时实施3次30 s的缺血和再灌注;Ⅲ组为远隔缺血后处理组,再灌注开始前实施5 min的右侧股动脉缺血;Ⅳ组为纳洛酮后处理组,再灌注开始时腹腔注射纳洛酮10 mg/kg;Ⅴ组为联合应用组.再灌注2 h和24 h时测定大鼠的神经功能障碍评分(NDS);再灌注24 h时,测定脑梗死区面积(n=10)、脑组织微管相关蛋白2(MAP2)表达(n=6)和脑组织血浆容量、血管直径和节段长度(n=6).结果 观察期所有时间点的心率和平均动脉压(MAP)组间比较差异均无统计学意义(均P＞0.05).再灌注24 h后,Ⅰ～Ⅴ组的缺血侧脑梗死面积与同侧大脑半球面积的比值(即脑梗死严重程度)分别是43%±6%、31%±4%、32%±5%、28%±6%和21%±7%.与Ⅰ组比较,Ⅱ～Ⅴ组的NDS和脑梗死严重程度均低(均P＜0.05),MAP2表达、血浆容量、血管直径和节段长度均高,但上述指标在Ⅱ组、Ⅲ组和Ⅵ组之间比较差异均无统计学意义(均P＞0.05).与Ⅰ组、Ⅱ组、Ⅲ组和Ⅳ组比较,Ⅴ组的NDS评分和脑梗死程度均低(均P＜0.05),MAP2表达和血浆容量显著高(均P＜0.05),但是缺血侧脑组织的血管直径和节段长度在Ⅱ组、Ⅲ组Ⅵ组和Ⅴ组之问差异均无统计学意义(均P＞0.05).结论 在局灶性脑缺血-再灌注损伤大鼠,缺血后处理、远隔缺血后处理和纳洛酮后处理均具有明显的神经保护作用,表现为脑梗死严重程度降低和神经功能障碍改善.联合应用3种后处理措施可获得增强的神经保护效应.

Abstract：

Objective To assess the effects of ischemic postconditioning, remote ischemic postconditioning and naloxone postconditioning on focal cerebral ischemia-reperfusion injury in rats.Methods A total of 110 adult SD rats were randomly divided into 5 groups (n =22 each). The focal cerebral ischemia-reperfusion injury was induced by a 90-minute occlusion of right middle cerebral artery (MCA) and a 24-hour reperfusion sequentially. Group 1 was of ischemia-reperfusion control; Group 2 ischemic postconditioning induced by three 30-second cycles of MCA occlusion followed by a 30-second reperfusion; Group 3 remote ischemic postconditioning performed via a transient occlusion of right femoralartery at 5 min before the initiatlon of reperfusion:Group 4 naloxone posteonditioning with naloxone 10 mg/kg intraperitoneaUy injected at the initiation of reperfusion;Group 5 combined ischemic,remote ischernic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2,3 & 4.The neumlogie deftcit scores(NDS)were obtained at 2 h & 24 h post-reperfusion.At 24 h post-reperfusion.the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to asseSS the size ofcerebral infaret(n=10),detect the cerebral expression of microtubule-associated protein2(MAP2)(n=6),measure the plasma volume of cerebral tissues and quantify the diameter and segment artery at 5 min before the initiation of reperfusion; Group 4 naloxone postconditioning with naloxone 10 mg/kg intraperitoneally injected at the initiation of reperfusion; Group 5 combined ischemic, remote ischemic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2, 3 & 4. The neurologic deficit scores ( NDS) were obtained at 2 h & 24 h post-reperfusion. At 24 h post-reperfusion, the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to assess the size of cerebral infarct (n = 10), detect the cerebral expression of microtubule-associated protein2 ( MAP2) (n =6) , measure the plasma volume of cerebral tissues and quantify the diameter and segment length of cerebral microvessel (n = 6 ). Results There were no significant differences in the heart rate (HR) and mean arterial pressure (MAP) among the above five groups at all observed time points (P ＞ 0. 05). At 24 h post-reperfusion, the percentage of ischemic cerebral infarct size was 43% ±6% , 31% ±4% , 32% ±5% , 28% ±6% & 21% ±7% in ipsilateral hemisphere area (i. e. , cerebral infarct severity)in Groups 1-5 respectively. Compared with Group 1, the levels of NDS and cerebral infarct severity significantly decreased at ischemic side in Groups 2-5 ( P ＜ 0. 05 ). And the cerebral expression of MAP2,plasma volume of cerebral tissues, diameter and segment length of cerebral microvessel significantly increased at the ischemic side (all P＜0. 05). However, there were no significant differences in the abovementioned parameters at ischemic side among Groups 2, 3 and 4 (all P ＞0. 05). The parameters of NDS,cerebral infarct severity, cerebral expression of MAP2 and plasma volume of cerebral tissues in the ischemic side significantly increased in Group 5 compared with Groups 1,2,3 and 4 (all P ＜ 0. 05). The diameter and segment length of cerebral microvessel at ischemic side were not different among Groups 2,3,4 and 5 (all P＞0. 05). Conclusion In focal cerebral ischemia-reperfusion rats, ischemic, remote ischemic and naloxone postconditioning may produce significant neuroprotective effects of reduced cerebral infarct severity and improved neurologic dysfunctions. A combination of three postconditioning approaches enhances the above neuroprotective effects.     

联合应用缺血后处理、远隔缺血后处理和纳洛酮后处理对大鼠脑缺血-再灌注损伤的影响

Objective To assess the effects of ischemic postconditioning, remote ischemic postconditioning and naloxone postconditioning on focal cerebral ischemia-reperfusion injury in rats.Methods A total of 110 adult SD rats were randomly divided into 5 groups (n =22 each). The focal cerebral ischemia-reperfusion injury was induced by a 90-minute occlusion of right middle cerebral artery (MCA) and a 24-hour reperfusion sequentially. Group 1 was of ischemia-reperfusion control; Group 2 ischemic postconditioning induced by three 30-second cycles of MCA occlusion followed by a 30-second reperfusion; Group 3 remote ischemic postconditioning performed via a transient occlusion of right femoralartery at 5 min before the initiatlon of reperfusion:Group 4 naloxone posteonditioning with naloxone 10 mg/kg intraperitoneaUy injected at the initiation of reperfusion;Group 5 combined ischemic,remote ischernic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2,3 & 4.The neumlogie deftcit scores(NDS)were obtained at 2 h & 24 h post-reperfusion.At 24 h post-reperfusion.the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to asseSS the size ofcerebral infaret(n=10),detect the cerebral expression of microtubule-associated protein2(MAP2)(n=6),measure the plasma volume of cerebral tissues and quantify the diameter and segment artery at 5 min before the initiation of reperfusion; Group 4 naloxone postconditioning with naloxone 10 mg/kg intraperitoneally injected at the initiation of reperfusion; Group 5 combined ischemic, remote ischemic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2, 3 & 4. The neurologic deficit scores ( NDS) were obtained at 2 h & 24 h post-reperfusion. At 24 h post-reperfusion, the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to assess the size of cerebral infarct (n = 10), detect the cerebral expression of microtubule-associated protein2 ( MAP2) (n =6) , measure the plasma volume of cerebral tissues and quantify the diameter and segment length of cerebral microvessel (n = 6 ). Results There were no significant differences in the heart rate (HR) and mean arterial pressure (MAP) among the above five groups at all observed time points (P ＞ 0. 05). At 24 h post-reperfusion, the percentage of ischemic cerebral infarct size was 43% ±6% , 31% ±4% , 32% ±5% , 28% ±6% & 21% ±7% in ipsilateral hemisphere area (i. e. , cerebral infarct severity)in Groups 1-5 respectively. Compared with Group 1, the levels of NDS and cerebral infarct severity significantly decreased at ischemic side in Groups 2-5 ( P ＜ 0. 05 ). And the cerebral expression of MAP2,plasma volume of cerebral tissues, diameter and segment length of cerebral microvessel significantly increased at the ischemic side (all P＜0. 05). However, there were no significant differences in the abovementioned parameters at ischemic side among Groups 2, 3 and 4 (all P ＞0. 05). The parameters of NDS,cerebral infarct severity, cerebral expression of MAP2 and plasma volume of cerebral tissues in the ischemic side significantly increased in Group 5 compared with Groups 1,2,3 and 4 (all P ＜ 0. 05). The diameter and segment length of cerebral microvessel at ischemic side were not different among Groups 2,3,4 and 5 (all P＞0. 05). Conclusion In focal cerebral ischemia-reperfusion rats, ischemic, remote ischemic and naloxone postconditioning may produce significant neuroprotective effects of reduced cerebral infarct severity and improved neurologic dysfunctions. A combination of three postconditioning approaches enhances the above neuroprotective effects.     

联合应用缺血后处理、远隔缺血后处理和纳洛酮后处理对大鼠脑缺血-再灌注损伤的影响

Objective To assess the effects of ischemic postconditioning, remote ischemic postconditioning and naloxone postconditioning on focal cerebral ischemia-reperfusion injury in rats.Methods A total of 110 adult SD rats were randomly divided into 5 groups (n =22 each). The focal cerebral ischemia-reperfusion injury was induced by a 90-minute occlusion of right middle cerebral artery (MCA) and a 24-hour reperfusion sequentially. Group 1 was of ischemia-reperfusion control; Group 2 ischemic postconditioning induced by three 30-second cycles of MCA occlusion followed by a 30-second reperfusion; Group 3 remote ischemic postconditioning performed via a transient occlusion of right femoralartery at 5 min before the initiatlon of reperfusion:Group 4 naloxone posteonditioning with naloxone 10 mg/kg intraperitoneaUy injected at the initiation of reperfusion;Group 5 combined ischemic,remote ischernic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2,3 & 4.The neumlogie deftcit scores(NDS)were obtained at 2 h & 24 h post-reperfusion.At 24 h post-reperfusion.the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to asseSS the size ofcerebral infaret(n=10),detect the cerebral expression of microtubule-associated protein2(MAP2)(n=6),measure the plasma volume of cerebral tissues and quantify the diameter and segment artery at 5 min before the initiation of reperfusion; Group 4 naloxone postconditioning with naloxone 10 mg/kg intraperitoneally injected at the initiation of reperfusion; Group 5 combined ischemic, remote ischemic & naloxone postconditioning performed simultaneously in accordance with the methods used in Groups 2, 3 & 4. The neurologic deficit scores ( NDS) were obtained at 2 h & 24 h post-reperfusion. At 24 h post-reperfusion, the anesthetized rat was sacrificed by decapitation and the brain rapidly extracted to assess the size of cerebral infarct (n = 10), detect the cerebral expression of microtubule-associated protein2 ( MAP2) (n =6) , measure the plasma volume of cerebral tissues and quantify the diameter and segment length of cerebral microvessel (n = 6 ). Results There were no significant differences in the heart rate (HR) and mean arterial pressure (MAP) among the above five groups at all observed time points (P ＞ 0. 05). At 24 h post-reperfusion, the percentage of ischemic cerebral infarct size was 43% ±6% , 31% ±4% , 32% ±5% , 28% ±6% & 21% ±7% in ipsilateral hemisphere area (i. e. , cerebral infarct severity)in Groups 1-5 respectively. Compared with Group 1, the levels of NDS and cerebral infarct severity significantly decreased at ischemic side in Groups 2-5 ( P ＜ 0. 05 ). And the cerebral expression of MAP2,plasma volume of cerebral tissues, diameter and segment length of cerebral microvessel significantly increased at the ischemic side (all P＜0. 05). However, there were no significant differences in the abovementioned parameters at ischemic side among Groups 2, 3 and 4 (all P ＞0. 05). The parameters of NDS,cerebral infarct severity, cerebral expression of MAP2 and plasma volume of cerebral tissues in the ischemic side significantly increased in Group 5 compared with Groups 1,2,3 and 4 (all P ＜ 0. 05). The diameter and segment length of cerebral microvessel at ischemic side were not different among Groups 2,3,4 and 5 (all P＞0. 05). Conclusion In focal cerebral ischemia-reperfusion rats, ischemic, remote ischemic and naloxone postconditioning may produce significant neuroprotective effects of reduced cerebral infarct severity and improved neurologic dysfunctions. A combination of three postconditioning approaches enhances the above neuroprotective effects.     

纳洛酮对大鼠心肌缺血再灌注损伤的影响

目的 观察纳洛酮(naloxone, NAL)对大鼠心肌缺血再灌注损伤的影响,并探讨其机制. 方法36只雄性SD大鼠随机分为空白对照组(Con组) 、缺血再灌注组(I/R组)、缺血预处理组(IPC组)和纳洛酮预处理组(Nal+I/R组),观察各组在缺血再灌注后的血流动力学变化、心肌梗死面积和心律失常发生情况,光镜下观察各组心肌超微结构的改变,用TUNEL检测法检测各组细胞凋亡情况. 结果与IR组相比,IPC组和Nal+I/R组均能明显改善缺血再灌注后心功能(P<0.05),减少心肌梗死面积(P<0.01)及心律失常的发生(P<0.01),保护心肌超微结构,减少凋亡指数(P<0.01). 结论纳洛酮对在体大鼠心肌缺血再灌注损伤心脏有保护作用,该研究拓宽了纳洛酮的临床用途,为防治缺血性心脏病提供了理论依据.     

延迟肢体缺血后处理对大鼠急性脑梗死后脑水肿的影响及其机制探讨

目的 观察延迟肢体缺血后处理对大鼠脑梗死后脑水肿的干预作用及Eph受体酪氨酸激酶-A2(EphA2)的变化规律,探讨延迟肢体缺血后处理减轻大鼠脑梗死后脑水肿的机制。方法 采用线栓法建立大鼠大脑中动脉闭塞模型。采用轮流夹闭双下肢股动脉主干,2min缺血/2min再灌注,各5个周期,连续5d进行肢体缺血后处理。比较脑组织含水量、伊文思兰(EB)含量,以及运用免疫组织化学染色检测各组EphA2的表达。结果 从2~5d,单纯再灌注各时间组脑组织含水量均明显高于延迟肢体缺血后处理各时间组(P<0.05); 单纯再灌注各时间组脑组织EB含量均明显高于延迟肢体缺血后处理各时间组(P<0.05); 与单纯再灌注组各时间点比较,延迟肢体缺血后处理组EphA2的阳性细胞数均明显降低(P<0.05)。单纯再灌注组于1d时EphA2就开始增多,2d达高峰,3d时出现下降; 延迟肢体缺血后处理变化趋势相同,但高峰值明显低于前者。结论 延迟肢体缺血后处理可能减轻脑梗死后脑水肿程度,其机制可能与抑制EphA2的表达有关。     

不同剂量纳洛酮治疗脑梗死临床观察

近年来应用纳洛酮治疗急性脑梗死较普遍，但其治疗剂量尚有争议。我科于2005-2006年应用大剂量纳洛酮治疗急性脑梗死，并与常规剂量纳洛酮进行对比研究，现报告如下。     

瑞芬太尼后处理对大鼠心肌缺血再灌注心律失常的影响

目的 观察瑞芬太尼后处理对大鼠心肌缺血再灌注心律失常的影响.方法 建立72只大鼠心肌缺血再灌注损伤模型.分为假手术组(Sham组)、缺血再灌注对照组(I-R组)、缺血后处理组(IPO组)和瑞芬太尼不同剂量后处理组(RPO1、RPO2、组),分别以2、4、6μg·kg-1,静脉泵注5 min,停止5min,重复进行3次.记录缺血30 min、再灌注40 min内心律失常评分,并取右室心肌组织行超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力、丙二醛(MDA)及钙离子(Ca2+)含量测定.结果 与I-R组比较,IPO组、RPO1组、RPO2组、RPO3组SOD、GSH-Px升高,Ca2+含量、MDA降低,心律失常评分降低(P＜0.05);与Sham组比较,I-R组、IPO组、RPO3组SOD、GSH-Px降低,MDA及Ca2+含量升高,心律失常评分升高(P＜0.05);IPO组与RPO组比较,各项指标差异无统计学意义(P＞0.05).结论 瑞芬太尼可模拟心脏缺血后处理作用,通过抗氧化及抑制钙超载来降低心肌缺血再灌注心律失常的发生.     

缺血后处理对大鼠肾脏缺血再灌注损伤的影响

目的 探讨缺血后处理对大鼠肾缺血再灌注(I/R)损伤的影响及其机制.方法 采用摘除右肾夹闭左侧肾蒂45 min再灌注6 h制备肾脏缺血再灌注损伤模型.2 w前已行右肾切除术的30只雄性SD大鼠随机分为3组(n=10):假手术组(S组)、缺血再灌注组(I/R组)和缺血后处理组(IPO组).IPO组在夹闭左侧肾蒂45 min后,再灌注10 s,缺血10 s,重复6次后,完全恢复肾血流.再灌注6 h处死大鼠抽取颈动脉血和切取左肾.测定血清肌酐(Cr)、尿素氮(BUN)浓度,肾组织中丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;光镜下观察肾组织病理学改变 ,采用流式细胞仪检测细胞凋亡率.结果 与S组比较,I/R组和IPO组Cr和BUN浓度升高,肾组织SOD活性降低,MDA含量升高,肾细胞凋亡率升高,病理损伤明显.与I/R组比较,IPO组Cr和BUN浓度降低,肾组织SOD活性升高,MDA含量降低,肾细胞凋亡率降低,病理损伤减轻.结论 缺血后处理能减轻大鼠肾缺血再灌注损伤,其机制与增强肾脏抗氧化能力和制肾组织细胞凋亡有关.     

辛伐他汀后处理对内皮细胞缺血再灌注损伤的影响

目的 观察辛伐他汀后处理对牛肺动脉内皮细胞缺血再灌注损伤的影响.方法 对牛肺动脉内皮细胞行5h的氧糖剥夺和1h的再灌注.在再灌注之初立即将不同剂量的辛伐他汀加入到内皮细胞中,抑制剂组加入相应的抑制剂.观察不同剂量辛伐他汀组、氧糖剥夺组、抑制剂组及对照组中LDH的释放水平.结果 辛伐他汀剂量依赖性地降低了氧糖剥夺和再灌注导致的乳酸脱氢酶释放,加入抑制剂可以逆转或消除他汀后处理的保护作用.结论 辛伐他汀后处理可以减少氧糖剥夺和再灌注导致的内皮细胞损伤.     

缺血后处理减轻大鼠局灶性脑缺血再灌注损伤最佳方案

目的探寻缺血后处理(IP)对大鼠局灶性脑缺血损伤保护作用的最佳时间,比较该处理方案与缺血预处理(IPC)脑保护效应.方法IP最佳时间确定实验分组60只雄性SD大鼠,随机分为6组(n=10).对照组,行单纯缺血再灌注;IP-15 s,30 s,1 min,2 min和5 min不同时间点组,分别于大脑中动脉线栓阻闭(MCAO)90 min后,再灌注15 s,30 s,1min,2 min和5 min,缺血15 s,30 s,1 min,2 min和5 min,反复三次,组间比较得出IP最佳时间.比较IP最佳时间与IPC脑保护效应实验分组30只雄性SD大鼠,随机分为3组(n=10).对照组,IP-15 s组和IPC组,预先阻闭大脑中动脉20min,再灌注24 h后行MCAO 90 min.上述实验90只动物经再灌注24 h后进行神经功能障碍评分.取大脑行2,3,5-氯化三苯四唑(TTC)染色确定脑梗死容积百分比,并行统计学分析.结果再灌注24 h后,在IP最佳时间的确定实验中,IP15 s组神经功能评分和脑梗死容积(34.0±4.8)%明显低于对照组[(58.9±12.2)%,P＜0.01];在IP与IPC脑保护效应比较实验中,IP-15 s和IPC的神经功能评分与对照组相比差异具有统计学意义(P＜0.01),但IP-15s脑梗死容积(36.1±10.3)%大于IPC组[(26.8±3.3)%,P＜0.01].结论IP对大鼠局灶性脑缺血损伤保护作用的最佳时间为15 s再灌注/缺血,反复三次;IP的脑保护效应弱于IPC.     

缺血后处理对大鼠局灶性脑缺血再灌注损伤保护作用的实验研究

目的:探讨缺血后处理对大鼠局灶性缺血再灌注损伤(ischemia reperfusion injury,IRI)的保护作用。方法:采用改良的Longa法建立大鼠右侧大脑中动脉缺血-再灌注损伤模型。健康雄性清洁级SD大鼠60只随机分为6组:假手术组和IRI组,缺血后处理(ischemia postconditioning,IPost)Ⅰ组、Ⅱ组、Ⅲ组、Ⅳ组。造模成功后,假手术组只暴露血管。IRI组阻断2 h,开放后不做任何处理。IPostⅠ~Ⅳ组分别开放15、30、60、120 s后,反复进行3个循环的阻断15 s/开放15 s,然后全面开放。于再灌注24 h检测肿瘤坏死因子α(tumor necrosis factorα,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)、IL-6及丙二醛(malondialdehyde,MDA)含量及超氧化物歧化酶(super oxide dismutase,SOD)活性;并制作脑组织病理切片,观察大鼠脑组织病理形态;TUNEL法检测大鼠脑海马神经细胞的凋亡。结果:IPostⅠ~Ⅲ组TNF-α、IL-1β、IL-6较IRI组明显下降(P<0.05)。与IRI组相比,IPostⅠ、Ⅱ组SOD活性明显升高(P<0.05)。IPostⅠ~Ⅲ组大鼠脑组织MDA含量较IRI组明显下降(P<0.05)。与IRI组比较,IPostⅠ、Ⅱ组凋亡神经细胞数明显降低(P<0.05)。结论:早期缺血后处理(1 min内)可减轻炎症反应和改善氧自由基代谢,减少了脑组织细胞的凋亡,对局灶性脑缺血再灌注损伤大鼠具有保护作用。     

雌二醇对大鼠脑缺血/再灌注损伤脑组织BDNF表达的影响

目的:观察雌二醇对大鼠脑缺血 /再灌注损伤脑组织脑源性神经营养因子 (BDNF)表达的影响。方法:64只Wistar大鼠随机分为局灶性脑缺血 2h/再灌注 3h、6h、12h、24h(A组)组及雌二醇治疗(100μg/kg) +脑缺血 2h/再灌注 3h、6h、12h、24h组(B组),每个时点 8只。2组采用线栓法建立大鼠局灶性脑缺血 /再灌注损伤模型。采用免疫组织化学法检测各组脑组织中BDNF蛋白的表达。结果:B组缺血再灌注后 3h、6h、12h、24h大脑皮层及纹状体BDNF阳性神经纤维密度较A组相应时点均明显增加 (P均 <0. 01);B组与A组比较,大脑皮层及纹状体BDNF阳性细胞数在再灌注后 6h开始增加, 12h明显增高 (P均 <0. 01), 24h恢复 (P>0. 05)。结论:雌二醇可以使大鼠脑缺血 /再灌注后脑组织内源性BDNF表达增加,而起到脑保护作用。     

局灶性脑缺血再灌注认知功能变化的实验研究

目的 观察不同时相缺血再灌注的大脑中动脉闭塞大鼠模型认知功能的变化.方法 36只SD大鼠,雌雄各半,分为假手术组、缺血30 min再灌注组、缺血90 min再灌注组.采用Longa线栓法制成年SD大鼠大脑中动脉闭塞(MCAO)模型.通过观察大鼠神经行为学评分、术后14 d红四氮唑(TTC)染色、水迷宫及听觉事件相关电位(P300)对认知功能的变化进行研究.结果 缺血30 min再灌注组、缺血90 min再灌注组大鼠神经行为学评分都在2分以上.大鼠术后第14天,TTC染色的结果显示2组缺血再灌注组大鼠的脑组织均有梗死灶.在定位航行实验、空间探索实验和听觉事件相关电位(P300)中,缺血90 min再灌注组大鼠和假手术组、缺血30 min再灌注组大鼠都存在明显差异(P＜0.01).结论 局灶性脑缺血再灌注大鼠的认知功能下降并随缺血时间的不同呈正相关改变.     

丙泊酚后处理对大鼠局灶性脑缺血再灌注损伤的改善作用及其机制

目的 探讨丙泊酚后处理对脑缺血再灌注损伤大鼠神经功能的改善作用及其对脑线粒体损伤的保护作用,阐明其作用机制。 方法 24只SD大鼠随机分为假手术组、模型组和丙泊酚后处理组,每组8只。模型组和丙泊酚后处理组大鼠采用结扎颈动脉法建立大脑中动脉阻塞局灶性脑缺血再灌注模型,丙泊酚后处理组大鼠于再灌注即刻股静脉输注20 mg·kg^－1·h^－1丙泊酚2 h,假手术组和模型组大鼠给予等量生理盐水。各组大鼠于再灌注24 h后进行神经功能缺损评分,采用HE染色法观察各组大鼠海马组织病理形态表现,采用相关试剂盒检测各组大鼠海马组织中氧化应激相关因子活性和水平,采用活性氧（ROS）荧光探针检测各组大鼠脑海马组织中ROS水平,采用TUNEL法检测各组大鼠海马组织中TUNEL阳性细胞率,采用Western blotting法检测各组大鼠海马组织中线粒体裂变、融合和生物发生相关蛋白及烟酰胺腺嘌呤二核苷酸磷酸酯氧化酶4（Nox4）和核因子E2相关因子2（Nrf2）蛋白表达水平,免疫荧光法检测各组大鼠海马组织中Nrf2蛋白表达水平。 结果 与假手术组比较,模型组大鼠神经功能缺损评分明显升高（P<0.05）,大鼠海马组织病理损伤明显,海马组织中超氧化物歧化酶（SOD）及谷胱甘肽过氧化物酶（GSH-Px）活性和总抗氧化力（T-AOC）水平明显降低（P<0.01）,丙二醛（MDA）和ROS水平及TUNEL阳性细胞率明显升高（P<0.05）,动力相关蛋白1（DRP1）、裂变蛋白1（Fis1）、Nox4和Nrf2蛋白表达水平明显升高（P<0.05）,视神经萎缩症蛋白1（OPA1）、线粒体融合蛋白2（Mfn2）、过氧化物酶体增殖物激活受体γ共激活因子1α（PGC-1α）和线粒体转录因子 A（TFAM）蛋白表达水平明显降低（P<0.05）;与模型组比较,丙泊酚后处理组大鼠神经功能缺损评分明显降低（P<0.05）,大鼠海马组织病理损伤明显改善,大鼠海马组织中SOD及GSH-Px活性和T-AOC水平明显升高（P<0.05）,MDA 水平、ROS水平和TUNEL阳性细胞率明显降低（P<0.05）,DRP1、Fis1和Nox4蛋白表达水平明显降低（P<0.05）,OPA1、Mfn2、PGC-1α、TFAM和Nrf2蛋白表达水平明显升高（P<0.05）。 结论 丙泊酚后处理可抑制脑缺血再灌注损伤大鼠海马组织细胞凋亡和氧化应激,促进线粒体融合和生物发生并抑制线粒体裂变,改善大鼠神经功能损伤,其机制可能与调控Nox4/Nrf2信号通路有关。     

红花黄素对大鼠局灶性脑缺血再灌注损伤的保护作用

目的 研究红花黄素对大鼠局灶性脑缺血再灌注损伤(I/R)的保护作用。方法 采用线栓法制作大鼠大脑中动脉缺血再灌注模型。插入栓线前、插入栓线0.5h后以及再灌注2h后分别监测肛温、肢体II导联心电、股动脉压以及大脑局部脑血流量。大鼠清醒后,进行行为学评分,测定脑含水量并进行组织病理学检查。结果 红花黄素能显著提高缺血再灌注后局部脑血流量,对抗血压与心率变化,降低脑组织含水量,缩小脑梗死面积,减轻缺血所致组织病理改变。结论 红花黄素可以增加I/R脑血流量,恢复因缺血造成的自主神经功能损伤,对大鼠局灶性脑缺血再灌注损伤具有保护作用。     

一氧化氮对大鼠局灶性脑缺血再灌注损伤的影响

目的观察L-精氨酸(L-Arg)和氨基胍(AG)对大鼠局灶性脑缺血组织中一氧化氮(NO)含量的影响,探讨NO对脑缺血再灌注损伤的作用及机制。方法将60只大鼠随机分为假手术组、模型组、L-Arg组和AG组,每组15只。L-Arg组、AG组、模型组和假手术组用线栓法建立大鼠局灶性脑缺血(MCAO)模型后,L-Arg组按500mg·kg-1腹腔注射1mLL-Arg注射液;AG组按100mg·kg-1术后腹腔注射1mLAG注射液;模型组和假手术组术后腹腔注射1mL灭菌生理盐水。观察缺血再灌注后12、24、72h大鼠行为学改变,血清中NO浓度和脑内一氧化氮合酶(NOS)分布的变化。结果与模型组相比,L-Arg组在缺血再灌注12h行为学评分显著降低(P<0.05),AG组在缺血再灌注24h行为学评分显著降低(P<0.05);AG组在缺血再灌注12h行为学评分高于L-Arg组(P<0.05)。与假手术组相比,模型组、L-Arg组和AG组缺血再灌注12、24、72h的NO含量均显著增加(P<0.05);与模型组相比,L-Arg组缺血再灌注12h的N0含量显著升高(P<0.05),AG组缺血再灌注24h的NO含量显著降低(P<0.05)。缺血再灌注12和24h,AG组的NO含量均显著低于L-Arg组(P<0.05);与假手术组相比,缺血再灌注12、24、72h的模型组、L-Arg组和AG组的iNOS阳性细胞均显著增加(P<0.05);与模型组相比,缺血再灌注12、24、72h的L-Arg组iNOS阳性细胞数差别无统计学意义(P>0.05);但AG组在3个时间点的iNOS阳性细胞数均显著低于模型组(P<0.05);AG组在3个时间点的iNOS阳性细胞数均低于L-Arg组(P<0.05)。结论脑缺血再灌注损伤后脑组织内NO和NOS的表达随时间动态变化,且NO在参与缺血性脑损伤过程中可能具有双重作用。L-Arg、AG通过不同的作用机制对大鼠局灶性脑缺血再灌注损伤具有保护作用。