急性氧化乐果中毒后脑水肿的MRI表现和病理改变对比研究

The experimental study of the brain MRI and the character of pathology after acute omethoate poisoning

目的:建立40％氧化乐果皮下染毒急性猫中毒模型,观察急性有机磷中毒脑损害的MRI影像学表现的发生发展规律,分析影像学表现与脑组织光镜、电镜病理改变的关系。方法将健康家猫25只,分为三组,对照组、染毒治疗组、染毒未治疗组。对照组(5只):即未染毒动物。染毒治疗组(简称染毒组)(15只):腹部皮下四点等量注射40％氧化乐果0.3ml/kg。染毒后2min肌肉注射0.5mg/kg硫酸阿托品,然后视动物流涎、流泪情况酌情肌注阿托品。染毒未治疗组( 5只):腹部皮下四点等量注射40％氧化乐果0.3ml/kg。对染毒后3小时,6小时、24小时脑MRI。表现与相应时间点脑组织光镜、电镜检查结果进行对照研究。结果:40％氧化乐果皮下染毒制作猫急性中毒模型,染毒后6小时、24小时MRI图像出现脑水肿。HE染色光镜和透射电子显微镜观察,3小时开始即出现广泛水肿表现,同时存在细胞毒性水肿和血管源性水肿,三者形态学表现相符。电镜示血脑屏障出现形态学变化,延髓24小时、6小时电镜切片中观察到神经元细胞质近三角形类晶体样物质。结论:氧化乐果染毒急性脑水肿的模型成功建立,中毒后脑水肿为混合性水肿,MRI出现异常表现稍晚于病理改变。

Objective; To establish the cat acute 40% omethoate subcutaneous poisoning model, to observe the occurrence and development of the sign of poisoning brain MR imaging, to analyze the relation between the MR imaging and the pathology by light microscope and transmissional electron microscope. Methods; 25 healthy cats were divided into three groups; control group, poisoning group (with atropine) , poisoning group (without atropine). The cats in control group were normal. The cats in poisoning group( with atropine) were injected 40% omethoate 0. 3ml/kg subcutaneous. 0. 5ml/kg atropine was administrated after 2 minutes from omethoate injection, then atropine was given regarding to the sweeping and salivating. The cats in poisoning group( without atropine) only administrated 40% omethoate 0. 3ml/kg subcutaneous. At observed time animals were scanned by MRI and were observed in condition of HE stain light microscope, transmissional electron microscope. Results; The MR imaging after 40% omethoate poisoning 6 hour and 24 hour showed brain edema. The cytotoxic brain edema and vasogenic brain edema existed from 3 hour to 24 hour showed by the results of HE light microscope and transmissional electron microscope. The photography of transmissional electron microscope presented blood brain barrier was damaged and triangular crystal substance in the cytoplasm. Conclusions; The brain edema model of acute 40% omethoate subcutaneous poisoning was successfully established. The edema in acute omethoate poisoning was mixed edema. The present of edema by MRI was later than pathological change.