壳聚糖对PM_(2.5)所致小鼠急性肺损伤的干预作用

Intervention effect of chitosan on acute lung injury induced by PM_(2.5) in mice

目的探讨壳聚糖对PM_(2.5)所致小鼠急性肺损伤的干预作用。方法将44只雄性C57BL/6J小鼠随机分为4组,即对照组、PM_(2.5)组、壳聚糖组及壳聚糖+PM_(2.5)组。壳聚糖+PM_(2.5)、壳聚糖组提前2周灌胃壳聚糖,对照组和PM_(2.5)组灌胃蒸馏水,每天1次。2周后PM_(2.5)暴露组气管滴注PM_(2.5),对照组和壳聚糖组滴注生理盐水,每天1次,连续7 d。末次染毒24 h后处死动物。HE染色形态学观察,分光光度法测定肝丙二醛(MDA)、肺泡灌洗液(BALF)中总蛋白(TP)和乳酸脱氢酶(LDH)水平;ELISA法测定BALF和血清中白介素-1β(IL-1β)、白介素-8(IL-8)及肿瘤坏死因子-α(TNF-α)表达。结果PM_(2.5)组肺泡间隔显著增宽,其内有明显的淋巴、浆细胞浸润;相对于PM_(2.5)组,壳聚糖+PM_(2.5)组肺间隔明显变窄,其内淋巴、浆细胞浸润明显减少。与对照组比较,PM_(2.5)组MDA、TP、LDH、TNF-α、IL-1β和IL-8明显升高(P<0.05);与PM_(2.5)组比较,提前补充壳聚糖,MDA、TP、LDH、TNF-α、IL-1β和IL-8明显降低(P<0.05)。结论提前摄入一定剂量的壳聚糖,对PM_(2.5)所致肺损伤有一定的干预作用。

Objective To explore the intervention effect of chitosan on acute lung injury induced by particulate matter with a diameter≤2.5μm(PM_(2.5))in mice.Methods Forty-four specific pathogen-free male C57 BL/6 J mice were randomly divided into four groups:control,PM_(2.5),chitosan and chitosan+PM_(2.5) groups.Animals from the chitosan+PM_(2.5) and chitosan groups were intragastrically administered chitosan daily for 2 weeks,and animals from the control and PM_(2.5) exposure groups were intragastrically administered distilled water once a day.After 2 weeks,the PM_(2.5) group was exposed to PM_(2.5)(4 mg/kg BW)via intratracheal instillation,whereas the control and chitosan groups were exposed to tracheal inhalation of normal saline,daily for 1 week.Animals were examined 24 h after the last exposure.Hematoxylineosin(HE)staining was used for morphological observation.The levels of malondialdehyde(MDA),total protein(TP)and lactate dehydrogenase(LDH)in alveolar lavage fluid(BALF)and liver samples were determined by spectrophotometry.The expression of interleukin-1β(IL-1β),interleukin-8(IL-8)and tumor necrosis factor-α(TNF-α)in BALF and serum were determined by ELISA.Results HE staining showed that the alveolar septum was significantly widened in PM_(2.5) group,and there was obvious infiltration of lymphoid and plasma cells.The lung septum was markedly narrowed in the chitosan+PM_(2.5) group compared with the PM_(2.5) group,and infiltration of lymph and plasma cells was significantly decreased in the chitosan+PM_(2.5) group versus the PM_(2.5) group.Compared with the control group,LDH,MDA,TP,TNF-α,IL-1βand IL-8 were significantly increased in the PM_(2.5) group(P<0.05).Compared with the PM_(2.5) group,the levels of LDH,MDA,TP,TNF-α,IL-1βand IL-8 were significantly decreased in the chitosan+PM_(2.5) group(P<0.05).Conclusions The intake of a certain dose of chitosan had a positive intervention effect on lung injury caused by PM_(2.5).