人工寒潮和热浪对易卒中型肾血管性高血压大鼠脑卒中的影响

Effects of artificial cold and heat waves on stroke in stroke-prone renovascular hypertensive rats

目的探讨人工寒潮和热浪对易卒中型肾血管性高血压大鼠(RHRSP)脑卒中发病的影响。方法健康雄性4~6周龄的SD大鼠随机分为实验组(24只)、假手术组(8只)和对照组(8只),实验组通过双肾双夹法建立RHRSP大鼠模型,将建模成功的24只RHRSP大鼠随机分为寒潮组、热浪组和正常气候组,每组各8只。利用RXZ-436A智能人工气候箱对实验组大鼠模拟寒潮、热浪和恒温恒湿天气,并在经历智能人工气候箱前后测量血压值并进行神经功能评分,3 d后处死各组大鼠并留取组织标本,首先观察有无脑出血情况,然后行TTC染色观察脑梗死情况,进行HE染色,观察脑组织病理学情况。采用重复测量方差分析和LSD检验比较对照组、假手术组和实验组大鼠在不同时间点(术前,术后4周,8周,12周)血压值的差异,采用单因素方差分析和LSD检验比较对照组、假手术组和实验组大鼠组间和实验组3亚组间在人工气候箱处理前后的血压值差异;采用配对t检验比较实验组大鼠组内人工气候箱处理前后的血压值的差异;采用χ^(2)检验和Fisher精确检验分析各组大鼠脑卒中发病情况。结果实验组术后12周血压值大于术后8周、术后4周和术前[(196.63±18.40)mmHg vs(169.43±13.41)mmHg vs(143.80±6.63)mmHg vs(111.37±7.65)mmHg],差异均具有统计学意义(P均<0.05)。人工气候箱处理后,寒潮组血压大于正常气候组和热浪组[(225.40±19.29)mmHg vs(204.20±8.71)mmHg vs(188.68±10.01)mmHg],差异具有统计学意义(P均<0.05)。寒潮组组内人工气候箱处理后的血压大于处理前[(225.40±19.29)mmHg vs(204.22±18.74)mmHg],热浪组处理后血压小于处理前[(188.68±10.01)mmHg vs(205.48±13.73)mmHg],差异具有统计学意义(t=-2.789、3.586,P=0.027、0.009)。将寒潮组和热浪组合称为极端天气组,极端天气组中脑卒中发病大鼠8只,其中寒潮导致的脑梗死3只,脑出血2只,热浪导致的脑梗死2只,脑出血1只,正常气候组脑卒中发病大鼠0只,极端天气组大鼠脑卒中总发病数高于正常气候组,差异具有统计学意义(χ^(2)=6.000,P=0.022)。结论人工寒潮和热浪可以增加RHRSP大鼠脑卒中的发病风险。

Objective To investigate the effects of artificial cold wave and artificial heat wave on stroke onset in stroke-prone medium-sized renal vascular hypertensive rats(stroke-prone renovascular hypertensive rats,RHRSP).Methods Healthy male SD rats(4-6 weeks old)were randomly assigned into experimental group(n=24),sham-operated group(n=8),and control group(n=8).Twenty-four successfully modeled RHRSP rats were randomly assigned into cold wave group,heat wave group,and normal climate group,with 8 rats in each group.After 3 days,the rats in each group were executed and tissue specimens were collected to dete the presence of cerebral hemorrhage,then TTC staining was performed to observe the cerebral infarction,and HE staining was performed to detect the histopathology of the brain.Repeated measures analysis of variance and LSD test were used to compare the differences in blood pressure of rats in each group at different time points(before operation,4 weeks,8 weeks,and 12 weeks after operation).One-way analysis of variance and LSD test were used to compare the differences in blood pressure among groups of rats before and after artificial climate chamber treatment.Paired t test was used to compare the difference of blood pressure before and after treatment with artificial climate box in each group.Chi-square test and Fisher's exact test were used to analyze the incidence of stroke in each group.Results The blood pressure value of the experimental group at 12 weeks after operation was higher than that at 8 weeks after operation,4 weeks after operation,and before operation[(196.63±18.40)mmHg vs(169.43±13.41)mmHg vs(143.80±6.63)mmHg vs(111.37±7.65)mmHg],and the difference was statistically significant(P<0.05).After the artificial climate chamber treatment,the blood pressure of the cold wave group was higher than that of the normal room temperature group,and the heat wave group[(225.40±19.29)mmHg vs(204.20±8.71)mmHg vs(188.68±10.01)mmHg],and there was a significant difference(P<0.05).In the cold wave group,the blood pressure after artificial climate box treatment was higher than that before treatment[(225.40±19.29)mmHg vs(204.22±18.74)mmHg],and there was a significant difference(t=-2.789,P=0.027).In the heat wave group,the blood pressure after artificial climate box treatment was lower than that before treatment[(188.68±10.01)mmHg vs(205.48±13.73)mmHg]and there was a significant difference(t=3.586,P=0.009).The combination of cold and heat wave group was called the extreme weather group.There were 8 cases of stroke in the extreme weather group,including 3 cases of cerebral infarction caused by cold wave,2 cases of cerebral hemorrhage,2 cases of cerebral infarction caused by heat wave,1 case of cerebral hemorrhage,and 0 cases in the normal climate group.The total number of stroke cases in the extreme weather group was significantly different from that in the normal climate group(χ^(2)=6.000,P=0.022).Conclusion Artificial cold wave and heat wave can increase the risk of stroke in stroke-prone renovascular hypertensive rats with renal vascular hypertension.