鱼油对PM_(2.5)所致大鼠肺损伤的干预作用

Effect of fish oil on lung injury induced by PM_(2.5) in rats

目的探索鱼油对PM_(2.5)气管滴注所致肺损伤的干预作用。方法采用醋酸纤维酯膜收集2015年11月至2015年12月新乡市的PM_(2.5)样品,用生理盐水制成悬液备用。36只Wistar雄性大鼠按完全随机设计分为生理盐水对照组、PM_(2.5)染毒组(6 mg·kg^(-1))、溶剂(玉米油)对照组、溶剂+PM_(2.5)组、低剂量鱼油+PM_(2.5)组和高剂量鱼油+PM_(2.5)组,每组6只。生理盐水组和PM_(2.5)染毒组大鼠正常饲养3周后,分别用生理盐水和PM_(2.5)悬液气管滴注,隔日1次,共3次。溶剂对照组大鼠用玉米油灌胃3周,之后用生理盐水气管滴注。溶剂+PM_(2.5)组、低剂量鱼油+PM_(2.5)组和高剂量鱼油+PM_(2.5)组大鼠分别用玉米油和鱼油灌胃3周,之后用PM_(2.5)悬液气管滴注染毒,隔日1次,共3次。各组大鼠末次处理后24 h进行支气管肺泡灌洗,测定支气管肺泡灌洗液(BALF)上清中总蛋白(TP)、乳酸脱氢酶(LDH)、白细胞介素-1β(IL^(-1)β)和肿瘤坏死因子-α(TNF-α)水平。未灌洗的右肺经甲醛固定后制作病理切片,观察肺组织的病理学变化。结果 PM_(2.5)染毒组大鼠肺组织病理切片显示大量炎性细胞浸润,肺泡壁增厚,肺间质增宽;低剂量鱼油+PM_(2.5)组、高剂量鱼油+PM_(2.5)组大鼠肺组织仅有轻微炎性细胞浸润。生理盐水对照组与溶剂对照组大鼠BALF中TP、LDH、IL^(-1)β、TNF-α水平比较差异均无统计学意义(P>0.05),PM_(2.5)染毒组和溶剂+PM_(2.5)组大鼠BALF中TP、LDH、TNF-α、IL^(-1)β水平增高(P<0.05);与PM_(2.5)染毒组比较,溶剂+PM_(2.5)组大鼠BALF中TP、LDH水平降低(P<0.05),TNF-α、IL^(-1)β水平比较差异无统计学意义(P>0.05);与PM_(2.5)染毒组比较,低剂量鱼油+PM_(2.5)组、高剂量鱼油+PM_(2.5)组大鼠BALF中TP、LDH、TNF-α、IL^(-1)β水平降低(P<0.05);与溶剂+PM_(2.5)组比较,低剂量鱼油+PM_(2.5)组、高剂量鱼油+PM_(2.5)组大鼠BALF中TP、LDH、TNF-α、IL^(-1)β水平均降低(P<0.05);与高剂量鱼油+PM_(2.5)组比较,低剂量鱼油+PM_(2.5)组大鼠BALF中TP、TNF-α水平降低(P<0.05),LDH、IL^(-1)β水平比较差异无统计学意义(P>0.05)。结论 PM_(2.5)可导致大鼠呼吸道损伤,鱼油能减少炎性因子的释放,对PM_(2.5)所致大鼠肺损伤具有明显的保护作用。

Objective To evaluate the effect of fish oil on PM2.5-induced lung injury in rats. Methods PM2.5specimen was collected by acetate membranes in Xinxiang city from November 2015 to December 2015. The dried samples were diluted into suspension with sterilized physiological saline before use. Thirty-six Wistar male rats were randomly divided into saline control group,PM2.5exposure group（ 6 mg·kg^-1,solvent（ corn oil） control group,solvent plus PM2.5group,low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group,six rats in each group. The rats in saline control group and PM2.5exposure group were fed normally for three weeks,then the rats were treated with saline and PM2.5suspension by tracheal instillation once every other day for three times. The rats solvent control group were administrated with corn oil by intragastric administration for three weeks before intratracheal instillation of saline once every other day for three times. The rats in solvent plus PM2.5group,low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group were administrated with corn oil and fish oil by intragastric administration for three weeks before intratracheal instillation of PM2.5once every other day for three times. Twenty-four hours after the last instillation,the rats were sacrificed and performed with alveolar wash. The levels of total protein（ TP）,lactate dehydrogenase（ LDH）,interleukid^-1β IL^-1β and tumor necrosis factor-α（ TNF-α） in lavage fluid were determined by kit. The right lung without lavage was used to make pathological section by formalin fixation and the pathological changes of lung tissue were observed. Results The inflammatory cell infiltration,thickened alveolar walls and increased alveolar spaces were found by the lung biopsy of rats in PM2.5exposure group. There was a small amount of inflammatory cell infiltration in the lung tissues of rats in low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group.There was no significant difference in the levels of TP,LDH,IL^-1βand TNF-α in BALF between solvent control group and saline control group（ P〉0. 05）. The levels of TP,LDH,IL^-1βand TNF-α in BALF of rats in PM2.5exposure group and solvent plus PM2.5group were significantly higher than those in saline control group（ P〈0. 05）. The levels of TP and LDH in BALF of rats in solvent plus PM2.5group were significantly lower than those in PM2.5exposure group（ P〈0. 05）. There was no significant difference in the levels of IL^-1βand TNF-α in BALF between solvent plus PM2.5group and PM2.5exposure group（ P〉0. 05）. The levels of TP and LDH in BALF of rats in low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group were significantly lower than those in PM2.5exposure group（ P〈0. 05）. There was no significant difference in the levels of IL^-1βand TNF-α in BALF between low dose of fish oil plus PM2.5group or high dose of fish oil plus PM2.5group and PM2.5exposure group（ P〉0. 05）. The levels of TP,LDH,TNF-α and IL^-1βin BALF of rats in low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group were significantly lower than those in solvent plus PM2.5group（ P〈0. 05）. The levels of TP and TNF-α in BALF of rats in low dose of fish oil plus PM2.5group were significantly lower than those in high dose of fish oil plus PM2.5group（ P〈0. 05）. There was no significant difference in the levels of LDH and IL^-1βin BALF between low dose of fish oil plus PM2.5group and high dose of fish oil plus PM2.5group（ P〉0. 05）. Conclusion PM2.5exposure can damage the respiratory tract of rats. Fish oil has a protective effect on lung injury induced by PM2.5in rats through reducing the release of inflammatory factors.