一氧化碳中毒所致迟发性脑病大鼠模型的建立

目的　建立一氧化碳 (CO)中毒迟发性脑病大鼠模型。方法　将 40只Wistar大鼠随机分为 4组 ,每组 10只。分别将大鼠放入内置式 +室中毒箱的中毒室内 ,A、B、C 3组分别通入体积分数为 10 0× 10 -4 、15 0× 10 -4 、16 5× 10 -4 的CO混合气体 ,D组通入空气 ,前 5h气体流量为 80 0L/h ,中间 4h为 10 0 0L/h ,最后 3h为 12 0 0L/h ,共通气 12h。中毒前后进行迷宫试验。中毒后 3～ 2 8d内出现昏迷或迷宫实验正确入臂数少于 3次者定为迟发性脑病大鼠。采用TUNEL法、流式细胞仪和透射电镜技术检测大脑皮质、海马部位细胞凋亡情况。结果　B、C 2组均有 4只大鼠出现迟发性脑病行为改变 ,A、D 2组则无改变。迟发性脑病大鼠凋亡细胞数TUNEL法检测 ,B组为 45 0 %～ 6 5 0 % ,C组为 5 5 0 %～ 80 0 % ,凋亡细胞主要为神经元 ;流式细胞仪检测 ,B组为 5 0 5 %± 4 2 % ,C组为 5 5 9%±7 8% ;电镜检测有典型凋亡改变的神经元 ,B组为 5 0 %～ 15 0 % ,C组为 10 0 %～ 2 0 0 %。A组凋亡细胞数均少于 5 0 % ,D组均少于 1 6 %。结论　以CO体积分数 15 0× 10 -4 ～ 16 5× 10 -4 、中毒时间12h建立的CO中毒迟发性脑病大鼠模型是成功的 ,其组织病理学改变为大脑皮质和海马的大量神经元凋亡。

Establishment of delayed encephalopathy rat model of carbon monoxide poisoning

OBJECTIVE: To establish the delayed encephalopathy rat model of carbon monoxide (CO) poisoning. METHODS: 40 Wistar rats were randomly divided into 4 groups of 10 rats and were placed in the chambers of inside-built 10-chamber poisoning box. Mixed gas is ventilated with the volume fractions of 10.0 x 10(-4), 15.0 x 10(-4) and 16.5 x 10(-4) of CO in air into the chambers for group A, B and C respectively, and pure air was ventilated for group D. The gas flow rate was 800 L/h in the first 5 hours, 1,000 L/h in the middle 4 hours, and 1,200 L/h in the last 3 hours, with a whole ventilation time of 12 hours. Before and after CO poisoning maze test with radial eight-arm maze was conducted to assess the rats' intelligence. The appearance of coma or less than 3 correct arm-enterings in maze test between the 3rd and 28th day after poisoning was considered as the indications of delayed encephalopathy. TUNEL method, flow cytometry, and transmission electron microscopy were adopted to examine the cellular apoptosis in cerebral cortex and hippocampus area. RESULTS: There were 4 rats with delayed encephalopathy changes in groups B and C respectively, while no similar behavioral change appeared in groups A and D. TUNEL method showed an apoptotic rate of 45.0% to 65.0% in the rats with delayed encephalopathy of group B and an apoptotic rate of 55.0% to 80.0% in the rats with delayed encephalopathy of group C, most of the apoptotic cells being neurons. Flow cytometry showed an apoptotic rate of 50.5% +/- 4.2% in the rats with delayed encephalopathy of group B and an apoptotic rate of 55.9% +/- 7.8% in the rats with delayed encephalopathy of group C. By electron microscopy the percentage of typical apoptotic neurons was 5.0% approximately 15% in group B and 10.0% to 20.0% in group C, less than 5.0% in group A, and less than 1.6% in group D. CONCLUSION: A delayed encephalopathy rat model of CO poisoning has been successfully established based on the volume fraction of 15.0 x 10(-4) to 16.5 x 10(-4) of CO in air and a poisoning time of 12 hours. The pathological change is a mass neuron apoptosis in cerebral cortex and hippocampus.