【作者】 王琳；

【导师】 蔡宏伟；

【作者基本信息】 中南大学 ， 麻醉学， 2010， 硕士

【摘要】 目的：本实验研究通过观察大鼠在控制性阈值(MAP=55mmHg)低血压持续不同时间的耐受情况,推断控制性阈值低血压持续的安全时限和脑组织损伤的发生发展情况。方法：SD大鼠随机分为4小组,每组6只大鼠：A组,手术对照组；C组,持续控制性MAP55mmHg水平组。C组又依降压持续时间设3个时间点：2h、4h、6h,依次对应为Cl、C2、C3组。术中用硝普钠复合艾司络尔诱导控制性低血压,行气管切开机械通气辅助呼吸,记录降压期间大鼠生命体征变化,行血气分析。术后24h观察大鼠神经行为学,生存率,并于处死前行血气分析。应用Tunel技术测定脑组织海马区细胞凋亡情况和免疫组化SP法测定脑红蛋白的表达水平。结果：1.C3组在低血压持续6h后的24h内,神经行为学表现低下,与A组、C1组和C2组相比较差异具有统计学意义(P<0.05),24h生存率为60%。其余各组生存率均为100%。2.海马区Tunel细胞凋亡指数(AI%)A组和C组组间比较：C2、C3组与A组比较差异有统计学意义(P<0.05)。C组组内比较：各组AI%随降压时间的延长而增加,其中：C2、C3组与Cl组比较,差异有统计学意义(P<0.05),C2组与C3组比较差异有统计学意义(P<0.05)。3.脑红蛋白免疫反应(Ngb-IR)阳性细胞数A组和C组相比有差异：C2、C3组与A组比较差异有统计学意义(P<0.05)。C组组内比较：C2、C3组Ngb-IR阳性细胞数表达增多,与C1组差异明显(P<0.05)；C3组Ngb-IR阳性细胞数较C2组减少,差异明显(P<0.05)。Ngb平均光密度(A)组间比较：C组呈阳性表达,与A组比较差异有统计学意义(P<0.05)；组内比较：C2组呈强阳性表达,与Cl组比较差异明显(P<0.01),C3组表达阳性,与Cl组相比差异据有统计学意义(P<0.05)；C3组与C2组相比,差异明显(P<0.01)。结论：一、SNP复合ESM诱导控制性MAP55mmHg持续6h后大鼠神经行为学明显低下,术后24h生存率60%。二、SNP复合ESM诱导控制性MAP55mmHg持续4h大鼠海马区细胞凋亡增多；持续6h细胞凋亡明显增多,提示脑组织损伤严重。三、SNP复合ESM诱导控制性MAP55mmHg持续4h大鼠海马区Ngb表达强阳性,持续6h Ngb表达转为阳性,提示神经元随降压时间的延长而出现不可逆性损伤。更多还原

【Abstract】 Objective:This research aimed to make clear about the time limit for the continued safety of the threshold(MAP=55mmHg)controlled hypotension and the mechanism of leading to brain injury, with the support of observations of the tolerance of the rat brain after threshold controlled hypotension at different time.Methods:SD rats were randomly divided into 4 groups, each group with 6 rats:Group A(normal);Group C(sustained controlled hypotension), Group C set three different points of sustained controlled hypotension:2h, 4h,6h. So 3 groups:C1, C2, C3. Use sodium nitroprusside (SNP) and esmolol (ESM) induced hypotension, using tracheotomy for mechanical ventilation. During the time of controlling blood pressure, recorded rats’ vital signs and did blood gas analysise.24-hour later, observed the rats’ neurobehavioral function and survival rate after hypotension, recorded the blood gas analysises again. Evaluated the apoptosis by Tunel and determined the expression of neuroglobin by immunohistochemistry of hippocampus.Result:(1) Assessment of the rats’neurobehavioral function:there were statistic difference (P<0.05) between group C3 and A. The survival rate after 24 hours of group C3 was 60%. Other groups were 100%.(3) A statistic difference of apoptosis-index(AI%) lied in group C2 and A(P<0.05). So was the C3and A. The group C2 group C3 were all had difference between group C1(P<0.05). There was great statistic difference between C3 and C2 (P<0.01).(4) There was statistic difference of neuroglobin immunoteactive (Ngb-IR) numbers between C and A(P<0.05). The Ngb-IR in the group C2 and C3 were more than C1(P<0.05). The statistic difference was also marked between group C2 and C3(P<0.01). Group C2 had the most Ngb-IR number. And the next one is group C3. The highest average optical density(A) lied in group C2(P<0.05), and the second one is C3 (P<0.05).Conclusions:(1) After hypotension of MAP55mmHg continued for 6h induced by SNP and ESM, rats’neurobehavioral function was severely damaged.(2) 4h hypotension of MAP55mmHg induced by SNP and ESM can had a notable changed on the AI% of hippocampus. Hypotension during 6h, the AI% was distinguished different between other groups.(3)Continued induced 4h hypotension of MAP55mmHg can made Ngb-IR a strongly expression. Continued for 6h can only lead Ngb-IR a waek expression. This indicated that the neurons showed an irreversible damage with the step-down time.更多还原