甲醛亚急性吸入暴露对大鼠肺组织损伤效应及炎性因子表达水平的影响

Effects of sub-acute formaldehyde inhalation on the damage to the lung tissue and on the expression level of cytokines in rats

目的 研究甲醛亚急性吸入暴露对大鼠肺组织损伤及炎性相关因子的影响.方法 6周龄雄性Wistar大鼠13只（中科院实验动物中心）,体质量（160±10）g,按数字表法随机分为正常对照组（对照组,6只）、甲醛亚急性吸入暴露组（暴露组,7只）.正常对照组在普通室内环境中饲养28 d;暴露组采用动态气溶胶染毒暴露系统,以舱内甲醛浓度（3.1 ±0.2）mg/m3为稳定暴露浓度,每天吸入2h,连续暴露28 d,第28天暴露后在普通室内环境中放置2h.然后将2组大鼠麻醉,取肺组织,行苏木精-伊红（HE）染色,观察肺组织结构变化,Tunnel原位显色法检测肺组织细胞损伤,ELISA方法测血清白细胞介素-1β（IL-1β）、白细胞介素-8（IL-8）、肿瘤坏死因子-α（TNF-α）、clara细胞分泌蛋白（CC10）因子分泌水平,实时荧光定量PCR （realtime-PCR）方法检测暴露后大鼠肺组织炎性相关因子TNF-α、IL-1α、IL-1β,以及CASP8凋亡调控因子（Cflar）、B淋巴细胞瘤因子-3（Bcl-3）、巨噬细胞胶原结构受体（Macro）、clara细胞分泌蛋白同源因子（Scgb1a1）表达水平的变化.结果 形态学观察表明,与对照组比较,暴露组大鼠肺泡间隔增宽,肺间质水肿,肺组织内炎性细胞侵润明显,凋亡细胞数明显增加.血清学检测结果表明,暴露组大鼠血清促炎因子水平IL-1β、TNF-α分别为（212.2±108.7）、（375.7±103.9） pg/L,较对照组[（143.8±76.5）、（137.2±112.2）pg/L]明显升高,2组比较差异有统计学意义（P＜0.05或P＜0.01）;暴露组抗炎因子CC10水平[（65.2±46.3） pg/L]比对照组[（160.1±89.1） pg/L]明显下降（P＜0.05）;2组IL-8差异无统计学意义（P＞0.05）.Reahime-PCR检测结果与血清学检测结果趋势一致.结论 甲醛亚急性吸入暴露28 d后,大鼠肺组织促炎因子表达、释放,抑制炎性修复因子表达,造成肺组织明显损伤、修复能力降低.

Objective To study the effects of sub-acute formaldehyde inhalation on the damage to the lung tissue and on the expression levels of related cytokines in rats.Methods Thirteen male Wistar rats （from the Experimental Animal Center of the Chinese Academy of Sciences） with an age range of 6 weeks and average body mass of （160 ± 10） g were randomly divided into the control group （n =6） and the sub-acute formaldehyde inhalation group （n =7）.The animals in the normal control group were kept in the general indoor space for 28 days,while the animals in the sub-acute formaldehyde inhalation group by the access of an aerosol dynamic exposure system were exposed to a stable formaldehyde concentration of （3.1 ± 0.2） mg/m3 through inhalation 2 hours a day and for a duration of 28 days.After 28 days of exposure,the animals were placed in the general indoor space for 2 days and were then anesthetized for the collection of the lung tissue,and changes in morphology of lung tissue was detected by HE staining.The damage of lung epithelial cells was monitored by Tunnel chromogenic in situ detection.The levels of Iβ（IL-1β）,IL-8,TNF-α,CC10 were detected by ELISA.Changes in the expression levels of TNF-α,IL-1α,IL-1β,Cflar,Bcl3,Macro and Scgblal were assayed by real-time PCR.Results Morphological observation showed that the alveolar space in the animals of the experimental group was widened with pulmonary interstitial edema,inflammatory cell infiltration could clearly be seen in the lung tissue,and the number of apoptosis cells was obviously increased.Serological detection also indicated that the levels of IL-1β and TNF-α in the animals of the exposure group were （212.2 ± 108.7） and （375.7 ± 103.9）pg/L respectively,and their levels were significantly increased than those of the control group [（143.8 ±76.5）,（137.2 ± 112.2） pg/L].Statistical significance could be noted,when comparisons were made between the 2 groups（P ＜ 0.05 or P ＜ 0.01）.The levels of CC10 in the animals of the exposure group [（65.2 ± 46.3） pg/L] were obviously lower than those of the animals in the control group [（160.1 ± 89.1） pg/L] （P ＜ 0.05）.No statistical significance could be seen in the levels of IL-8,when comparisons were made between the 2 groups（P ＜ 0.05）.The results of real-time PCR and serological detection tended to be identical.Conclusions Formaldehyde inhalation sub-acute exposure for 28 days could promote the expression and release of inflammatory cytokines and inhibit the expression of inflammatory repair factors,resulting in obvious damage to the lung tissue and reduction of damaged cell repair.