高温高湿环境对犬脑组织的损害作用

Effect of high temperature and humidity environment on brain tissue damage of dogs

目的:观察犬暴露在高温高湿环境下,其生命指标变化及其热衰竭死亡后脑组织病理学改变特点。方法:选用市售杂种犬11只,分为常温对照组犤温度(22.20±1.30)℃,相对湿度<60%犦6只和高温高湿暴晒组犤温度(58.20±6.90)℃,相对湿度39%～52%,辐射热强度≥4.184J/(cm2·min)犦5只,观察两组动物实验前30min和实验后2h体温、呼吸和心率变化,及抽血行血气分析检测,并收集脑组织标本进行组织病理学检查。结果:两组比较,晒前30min两者差异无显著性意义,晒后1h高温高湿暴晒组动物体温升高10.18℃左右(t=-14.35,P=0.00)呼吸频率增加116.60次/min(t=-8.11,P=0.00)呈显著增高,二氧化碳分压、碳酸氢根离子、血浆二氧化碳总量明显降低(P皆<0.05),而氧分压、剩余碱、动脉血氧饱和度及pH值变化无显著性意义(P>0.05),其平均生存时间为74min,死亡后脑组织细胞结构疏松、神经元明显减少,伴有脑组织内斑片状出血。结论:高温高湿环境对犬脑组织有明显损害作用。

AIM:To observe the changes of vital indexes and the characteristics of brain histopathological changes in dogs after heat exhaustion death exposed to the environment of high temperature and humidity. METHODS:Eleven cross-bred dogs were divided into control group at common temperature[n=6, temperature:(22.20±1.30) ℃, relative humidity:< 60%]and exposed group in an environment of high temperature and humidity [n=5, temperature:(58.20±6.90) ℃, relative humidity: 39%-52%, intensity of radiant heat: ≥4.184].The body temperature,respiratory rate,heart rate and the blood gas analysis were measured 30 minutes before and 1 hour after experiment,and then the brain tissue specimens were collected for pathological examination in both groups. RESULTS:There were no significant differences between the two groups 30 minutes before exposure.One hour after exposure,the body temperature was increased by 10.18 ℃or so(t =-14.35,P=0.00) and respiratory rate was increased by 116.60 times per time (t=-8.11, P=0.00)in the exposed group in the environment of high temperature and humidity, in which the mean survival time was 74 minutes; the partial pressure of carbon dioxide(PCO2),HCO3-and total carbon dioxide(CO2)were obviously decreased (P< 0.05),while there were no distinct alterations in blood partial pressure of oxygen, base excess (BE),arterial oxygen saturation and blood pH concentration(P >0.05),and loose brain tissue structure,decreased neurons and spot haemorrage in brain tissues were observed. CONCLUSION:The environment of high temperature and humidity has obvious damaging effect on the brain tissue of dogs.