大鼠急性肺损伤肺组织中白细胞介素17的含量变化及异丙酚的影响

目的了解白细胞介素17（IL-17）在大鼠盐酸吸入性急性肺损伤（ALI）模型中的含量变化及意义,并观察异丙酚的影响。方法通过气管内吸入盐酸（0.1 mol/L,2 mL/kg）建立大鼠ALI模型。将35只成年健康雄性SD大鼠随机分为7组：对照组、盐酸组（HCl组）、异丙酚组。按异丙酚100 mg/kg腹腔注射时间再分为5个亚组：盐酸吸入前24 h注射异丙酚（T24b组）,盐酸吸入前12 h注射异丙酚（T12b组）,盐酸吸入即刻注射异丙酚（T0组）,盐酸吸入后1 h注射异丙酚（T1a组）,盐酸吸入后3 h注射异丙酚（T3a组）。酶联免疫吸附法（ELISA）测定肺组织匀浆及支气管肺泡灌洗液（BALF）中IL-17含量,免疫组织化学方法检测肺组织IL-17表达水平和部位;测定肺组织及BALF中IL-8浓度,肺组织髓过氧化物酶（MPO）活性;计算IL-17与MPO、IL-8的相关性。结果大鼠于盐酸吸入后很快出现呼吸急促、发绀、氧合指数降低、肺水肿、肺组织炎性细胞浸润、肺出血等典型ALI表现;与对照组比较,HCl组大鼠肺组织匀浆及BALF中IL-17含量均显著升高（106.03±13.90）pg/mg pro比（23.16±8.18）pg/mg pro;（65.99±19.02）pg/mg pro比（7.69±2.94）pg/mg pro,P均〈0.01];IL-17在HCl组大鼠肺组织中表达明显增加,主要表达在肺泡上皮细胞及肺间质单个核细胞,而正常大鼠仅在肺泡上皮细胞少量表达;HCI组大鼠肺组织匀浆IL-17升高与肺组织匀浆IL-8升高（r=0.98,P=0.003）及与MPO升高（r=0.981,P=0.003）均显著正相关,IL-8与MPO也显著正相关（r=0.961,P=0.009）。各时点异丙酚组大鼠氧合指数、肺水肿均有不同程度改善,其中以T24b组改善最明显;T24b组大鼠与HCl组比较,肺组织匀浆和BALF中IL-17（81.28±10.68）pg/mg pro比（106.03±13.90）pg/mg pro,P=0.011;（33.08±7.94）pg/mg pro比（65.99±19.02）pg/mg pro,P=0.003]及IL-8（7.77±1.08）pg/mg pro比（11.7±1.48）pg/mg pro;（2.91±0.65）pg/mg pro比（6.39±0.59）pg/mg pro,P均〈0.01],以及肺组织MPO活性（1.10±0.85）单位/克湿片比（1.51±0.25）单位/克湿片,P〈0.01]均显著下降,其他异丙酚组与HCl组比较,差异无显著性。结论 IL-17在大鼠盐酸吸入性ALI中显著升高。肺泡上皮细胞、肺间质单个核细胞可能是产生IL-17的主要细胞。IL-17可能通过刺激IL-8的产生,进而引起肺组织中性粒细胞的聚集而参与ALI的病理过程。预先给予异丙酚能明显减轻盐酸吸入大鼠肺损伤程度。降低IL-17的水平可能是异丙酚减轻肺损伤的机制之一。

Changes of Interleukin-17 in Lung Tissue and Effects of Propofol in Rats with Acute Lung Injury

Objective To investigate the changes of interleukin-17（IL-17） and the effects of propofol in rats with acute lung injury（ALI）.Methods ALI model was established by hydrochloric acid（HCl） inhalation in a dose of 2 mL/kg.35 adult male SD rats were randomly divided into seven groups,ie.a control group,a HCl group,and five propofol groups（T24b,T12b,T0,T1a,T3a groups,respectively）.The T0,T24b and T12b groups were pretreated with intraperitoneal propofol injection 0,24 and 12 hours respectively before HCl inhalation.The T1a and T3a groups were managed by intraperitoneal propofol injection 1 and 3 hours respectively after HCl inhalation.Immunohistochemistry was used to determine the expression of IL-17 in lung tissue.ELISA was adopted to detect the levels of IL-17 and IL-8 in lung tissue homogenate as well as in bronchoalveolar lavage fluid（BALF）,meanwhile arterial partial pressure of oxygen（PaO2） and myeloperoxidase（MPO） were measured.Results Those rats in the HCl group appeared respiratory distress,cyanosis,pulmonary edema,and inflammatory cells infiltration in lung tissues after HCl inhalation.The IL-17 levels in lung tissue homogenate as well as in BALF were higher in the HCl group than those in the control group（all P0.01）.IL-17 was mainly expressed in alveolar epithelial cells and mononuclear cells in the ALI rats and its expression level was higher than that in the control group.IL-17 concentration in lung tissue homogenate was both correlated with IL-8 concentration in lung tissue homogenate（r=0.98,P=0.003） and with the activity of MPO in lung tissue（r=0.981,P=0.003） in the HCl group.Mainwhile,a same significant correlation was found between IL-8 level in lung tissue homogenate and the MPO activity in the HCl group（r=0.961,P=0.009）. Propofol attenuated lung injury induced by HCl inhalation,especially in T24b group.The concentrations of IL-17 in lung tissue homogenate and in BALF were lower in T24b group when compared with the HCl group（P=0.011,P=0.003,respectively）.Conclusions The expression of IL-17 increases in ALI rats.Pretreatment with propofol by 24 hours has obvious inhibiting effects on inflammatory reaction.Inhibiting IL-17 expression may be one of the mechanisms through which propofol inhibits the inflammatory reaction of ALI.