炭黑暴露对小鼠脑组织炎症损伤的影响

Inflammatory injury induced by carbon black exposure in cerebral tissue of C57 mice

目的探讨炭黑暴露对小鼠脑组织炎症损伤的影响。方法将20只健康9周龄SPF级C57BJ/6雄性小鼠随机分为对照(空气)组和炭黑组,每组10只。应用动式吸入染毒的方法对炭黑组小鼠进行吸入染毒,染毒剂量为30 mg/m^3,每天6 h,连续14 d。应用苏木素-伊红(HE)染色观察小鼠皮质、海马组织的结构变化;采用酶联免疫吸附法(ELISA)测定小鼠海马、皮质、下丘脑、纹状体和嗅球中白细胞介素-4(IL-4)、白细胞介素-6(IL-6)的含量;应用Real-Time PCR方法检测小鼠皮质和海马IL-4、IL-6 mRNA的表达水平。结果与对照组相比,炭黑染毒小鼠皮质可见细胞核固缩,深染;海马区神经元细胞排列紊乱,细胞核固缩。与对照组比较,炭黑组小鼠皮质、海马及下丘脑中IL-4的水平均较高,差异有统计学意义(P<0.05);而纹状体、嗅球中IL-4的水平均无明显改变。与对照组比较,炭黑组小鼠皮质、海马、纹状体及下丘脑中IL-6的水平均较高,差异有统计学意义(P<0.05);而嗅球中IL-6的水平无明显改变。与对照组比较,炭黑组小鼠皮质、海马中IL-4、IL-6 mRNA表达的水平均较高,但仅海马中IL-4、IL-6 mRNA表达的水平差异有统计学意义(P<0.05)。结论炭黑染毒可引起小鼠脑组织中炎症因子表达增加,引发炎症反应,其中皮质、海马、下丘脑炎症损伤较为严重,这可能是炭黑致中枢神经系统损伤的机制之一。

Objective To investigate the inflammatory injury in cerebral tissues of mice exposed to carbon black（CB）. Methods A total of 20 healthy nine-week-old SPF grade male C57 BL/6 mice were randomly divided into control group and CB exposure group,10 in each. The mice in CB group were exposed to CB in the inhalation chamber at 30 mg/m^3,6 h/d,for 14 consecutive days. The pathological changes in the cortex and hippocampus were observed by HE staining. The expression levels of interleukin-4（IL-4）,interleukin-6（IL-6） protein and m RNA in cerebral tissues were determined by ELISA and real-time PCR. Results A large number of neurons in the cortex were degenerated and some neurons in the hippocampus were disordered,and with nuclear condensation in CB group. The IL-4 protein levels in cortex,hippocampus and hypothalamus in CB group were significantly higher than that in control group respectively（P 0.05）. There was no significant change in the expression levels of IL-4 protein of striatum and olfactory bulb in each group. The IL-6 protein contents in cortex,hippocampus,striatum and hypothalamus in CB group were significantly increased than that in control group respectively（P〈0.05）. There was no significant change in the expression levels of IL-6 protein of olfactory bulb in each group. Compared with the control group,the expression of IL-4 and IL-6 mRNA in both cortex and hippocampus of CB group were increased. But only the changes of IL-4 and IL-6 mRNA in hippocampus were significant（P〈0.05）. Conclusion Carbon black exposure may cause the increase of inflammatory factors in brain tissue,especially in cortex,hippocampus,hypothalamus serious,which may be one of the mechanisms of neurotoxicity induced by carbon black.