小鼠1,2-DCE中毒性脑水肿形成过程中不同脑区CYP2E1表达水平及其对脑水肿形成的影响

Expression of CYP2E1 in different brain regions during the formation of toxic cerebral edema induced by 1,2-DCE in mice and its effect on cerebral edema formation

目的研究1,2-二氯乙烷(1,2-dichloroethane,1,2-DCE)染毒过程中不同脑区细胞色素P450 2E1(cytochrome P-450 2E1,CYP2E1)表达的变化,探讨CYP2E1对1,2-DCE中毒引起的脑水肿形成的影响和作用。方法于2018年12月,选择雌性SPF级昆明种小鼠40只随机分为对照组、染毒1、2和3 d组共4组,每组10只。将染毒组小鼠置于100 L静式染毒柜中(5只/柜),以1.2 mg/L 1,2-DCE每天吸入染毒3.5 h,分别染毒1、2和3 d,对照组不进行染毒,其他处理方式与染毒组相同。分别于染毒结束后次日处死,取脑组织并分区,采用HE染色法对不同脑区进行组织病理学观察,检测不同脑区丙二醛(malondialdehyde,MDA)、还原型谷胱甘肽(glutathione,GSH)含量和过氧化氢酶(catalase,CAT)活力;同时以蛋白免疫印迹(Western blotting)法检测不同脑区中CYP2E1、occludin和claudin5蛋白含量,再以实时荧光定量PCR法检测CYP2E1、occludin和claudin5 mRNA表达水平。实验数据采用SPSS 20.0进行统计分析,多组组间比较采用单因素方差分析(one-way ANOVA),组间两两比较采用SNK(q检验)法分析。结果与对照组比较,染毒2 d和3 d组小鼠小脑组织出现明显的脑水肿改变;与对照组比较,染毒3 d组小鼠小脑组织中MDA含量、CYP2E1蛋白和mRNA表达水平明显增高,差异均有统计学意义(P<0.05);与对照组比较,各个染毒组小鼠小脑组织中GSH含量、CAT活力及occludin和claudin5蛋白表达水平明显降低,差异均有统计学意义(P<0.05)。各组小鼠额叶皮质组织中上述指标差异均无统计学意义(P>0.05)。结论 1,2-DCE染毒可以诱导小鼠小脑组织中CYP2E1的表达增强,引起脑组织氧化损伤和脑水肿,对小鼠额叶皮质组织中CYP2E1的表达无明显影响。

Objective To study the expression changes of cytochrome P-4502E1(CYP2E1)in different brain regions during 1,2-dichloroethane(1,2-DCE)exposure,and to explore the effect of CYP2E1 on the influence and effect of brain edema caused by 1,2-DCE poisoning.Methods In December 2018,forty female SPF Kunming mice were randomly divided into 4 groups:control group,1 d,2 d,and 3 d exposure groups,with 10 mice in each group.Placed in a 100 L static poisoning cabinet(5 animals/cabinet),inhaled and exposed to the poison at 1.2 mg/L 1,2-DCE for 3.5 h per day for 1 d,2 d and 3 d.Except for exposure to 1,2-DCE,other treatment methods were the same as those in the exposure groups.They were put to death the next day after the end of the poisoning,and the brain tissue was quickly removed and divided into sections.HE staining method was used for different brain regions.Western blotting method was used to detect the protein content of CYP2E1,occludin and claudin5 in different brain regions,real-time fluorescent quantitative PCR method was used to detect the mRNA expression levels of CYP2E1,occludin and claudin5.Histopathological observations were performed,and the kit method was used to detect malondialdehyde(MDA),reduced glutathione(GSH)content and catalase(CAT)activity in different brain regions.The experimental data were analyzed by SPSS 20.0.One-way analysis of variance(one-way ANOVA)was used for the comparison of multiple groups,and the SNK(q test)method was used for the pairwise comparison between groups.P<0.05 was considered statistically significant.Results Compared with the control group,histopathological observations showed obvious brain edema in the 2 d and 3 d exposure groups;Compared with the control group,the MDA content,CYP2E1 protein and mRNA expression levels in the cerebellar tissues of the mice in the 3 d exposure group were significantly increased,and the differences were statistically significant(P<0.05);Compared with the control group,the GSH content,CAT activity,occludin and claudin5 protein expression levels in the cerebellar tissues of the mice in each exposure group were significantly reduced,and the differences were statistically significant(P<0.05).There was no significant difference in the above indicators of frontal cortex in each group in mice(P>0.05).Conclusion 1,2-DCE can induce the expression of CYP2E1 in cerebellar tissues of mice,and cause oxidative damage and brain edema,but has no effect on the expression of CYP2E1 in frontal cortex of mice.