NQO1在tBHQ干预急性CO中毒后迟发性脑病大鼠海马区的表达及作用

摘要

目的 探讨醌氧化还原酶1(NQO1)在叔丁基对苯二酚(tBHQ)干预大鼠急性CO中毒后迟发性脑病(DEACMP)模型中海马区的表达及作用.方法 180只大鼠中随机抽样出60只作为空气对照组(AC组)、60只作为一氧化碳中毒组(CO组)、60只作为一氧化碳中毒+tBHQ组(TC组),,每组按染毒后1 d、3 d、7 d、14 d、21 d、28 d随机分为6个亚组,动态监测染毒前后大鼠动脉血中HbCO浓度,水迷宫实验检测大鼠平均逃避潜伏期、穿越平台频次、平台象限游泳时间记录其学习记忆能力的变化,Tunel法检测大鼠海马CA1区凋亡细胞,免疫组化法、Western Blot法检测大鼠海马区NQO1蛋白的表达情况.结果 成功建立120只大鼠急性CO中毒模型,TC、CO组大鼠的动脉血HbCO浓度持续超过16 h大于50％,且水迷宫实验发现以上两组大鼠在14 d开始出现学习记忆能力下降,且TC组大鼠变化较CO组更显著(P<0.05).TC、CO组大鼠的细胞凋亡指数均较AC组升高(P<0.05),呈现先升高后降低趋势,在7 d达凋亡高峰(7 d:TC组:23.041.89,CO组:25.522.11),TC组与CO组比较,1～7 d低于CO组,21～28 d高于CO组,差异具有统计学意义(P<0.05).TC、CO组大鼠海马CA1区NQO1的表达均较AC组升高(P<0.05),从1 d开始升高,3 d达峰点(TC组:9.560.83,CO组:8.080.58)而后缓慢下降的走势,且TC组与CO组、AC组各相同时间点比较差异具有统计学意义(P<0.05).结论 ACOP中毒后大鼠海马区NQO1的表达升高,与细胞凋亡情况呈正相关,在染毒后3 d内NQO1表达增加发挥抗氧化应激损伤的保护作用,而后NQO1继续高表达推动海马区细胞发生迟发性凋亡、促进DEACMP的发病.%Objective To investigate the expression of NQO 1 after tert-butylhydroquinone ( tBHQ) intervented those hippocampus of rats with delayed encephalopathy after acute carton monoxide poisoning ( DEACMP ) and its functions . Methods From 180 rats random drawing 60 rats as air control group (AC group), 60 rats as carbon monoxide poisoning group (CO group),60 rats as carbon monoxide poisoning +tBHQ group (TC group),and then divided into 6 subgroups after exposure,1 d、3 d、7 d、14 d、21 dand28 d according to the intraperitoneal injection of different solvents ,and the car-boxyhemoglobin ( HbCO) concentration in arterial blood was dynamic monitored .The Morris water maze was used to ob-served the average escape latency across the platform ,the platform quadrant swim time frequency to record the changes of learning ability and memory of rats ,Tunnel method was used to test the pyramidal cell apoptosis in the hippocampal CA 1 ar-ea.The expression of NQO1 was tested by immunohistochemical method and Western Blot method .Results DEACMP model was successfully established in 120 rats;The concentration of HbCO in rats continue to maintain more than 50％a-bove 16 hours throughout the course of exposure .The poisoned rats was found began to decline the ability of learning and memory in water maze test in the 14th day.Those changes in TC group was statistically significant (P<0.05) compared with CO group.The apoptosis index (AI) started to increase from first day and achieved it 's peak at the 7th day (7 d:TC group:23.041.89,CO group:25.522.11)in TC and CO group,then began to decrease slowly .But in the 1stday,3rdday and 7thday after exposured,the AI was significantly decreased(P<0.05),in the 21thday,28thday after exposured,the AI was significantly increased(P<0.05) compared with CO group.In TC and CO group the expression of NQO1 protein star-ted to increase from 1st day,reached its peak at 3rd day (TC group:9.560.83,CO group:8.080.58)and expressed signif-icantly higher than AC group at each time point (P<0.05).The difference between each peak point and that at other time points in the same group was statistically significant (P<0.05).Conclusion The NQO1 has a positively correlated with cell apoptosis ,and it rapidly increased in first 3 d to against oxidative stress injury after exposure play a protective effect . But it continuously has been excessive expressed driving the apoptosis of hippocampus pyramidal cells and may be an accel -eration of DEACMP .