不规则趋化因子在百草枯致大鼠急性肺损伤过程中的表达

目的 通过观察不规则趋化因子(fractalkine,FKN,又称CX3CL1)在百草枯(paraquat,PQ)中毒早期大鼠血清及肺组织的表达,探讨FKN在PQ致大鼠急性肺损伤的作用.方法 SD大鼠66只,随机(随机数字法)分为染毒组(36只)和对照组(30只).染毒组腹腔注入PQ (22 mg/kg),对照组给等量生理盐水.每组分别在染毒后6、12、24、72及120 h处死大鼠.测定肺脏系数,检测血清及肺组织匀浆FKN含量(ELISA法),观察肺组织病理改变(HE染色)及FKN的表达(免疫组化法).应用SPSS 19.0软件分析数据.结果 在各观察时间点(6、12、24、72及120 h),染毒组肺脏系数分别为(5.03 ±0.07、5.17±0.10、5.46±0.10、5.68±0.15及5.83±0.11),明显高于对照组(4.49 ±0.20、4.28±0.13、4.45±0.17、4.31 ±0.19及4.31±0.16),差异具有统计学意义(P＜0.01);染毒组血清FKN质量浓度(pg/mL)分别为140.9±15.8、157.9±17.6、188.8±24.8、224.4±18.1及229.9±10.0,明显高于对照组(121.7±12.8、121.6±12.1、118.3±14.0、122.8±12.4及120.5±8.8),差异具有统计学意义(6h时P＜0.05,其余P＜0.01);染毒组肺组织匀浆FKN质量浓度(pg/mL)分别为(4 222.0±641.1、5 021.0±514.5、5 911.6±478.1、7 092.2±652.9及7 639.3±666.6),明显高于对照组(2 860.2±477.3、3 068.9±446.0、3 168.7±728.5、3 178.0±488.2及3 147.3±426.6),差异具有统计学意义(P＜0.01).镜下观察,与对照组相比,染毒组大鼠肺组织病理改变为炎性细胞浸润、肺组织充血水肿及结构破坏等急性肺损伤表现,并随时间推移逐渐加重.FKN主要表达于支气管和肺泡上皮细胞、肺小动脉内皮细胞中,FKN表达增多的区域炎性细胞浸润增多.肺组织匀浆FKN含量与肺脏系数呈正相关(r=0.937),血清FKN含量与肺组织匀浆FKN含量呈正相关(r=0.968).结论 FKN与PQ致大鼠急性肺损伤的发病过程紧密相关.

Expression of fractalkine in acute lung injury induced by paraquat in rats

Objective To observe the expression of fractalkine (FKN or CX3CL1) in serum and lung tissue in early phases after paraquat (PQ) poisoning in rats,and to analyze the effect of FKN on acute lung injury induced by PQ.Methods A total of 66 SD rats were randomly (random number) divided into two groups,namely PQ group (n =36) and control group (n =30).Through intra-peritoneal route,PQ (22 mg/kg) was administered to PQ group,and an equal volume of normal saline to control group instead.Rats were separately sacrificed at 6 h,12 h,24 h,72 h and 120 h after poisoning.Lung coefficient was determined.The levels of FKN in serum and lung tissue homogenate were detected by ELISA.Lung pathological changes were observed by HE staining.FKN changes were investigated by immunohistochemistry staining.Data was analyzed by SPSS 19.0.Results From 6 h to 120 h after poisoning,parameter determined in PQ group had great changes,compared with the control group.At 6 h,12 h,24 h,72 h and 120 h,lung coefficients in PQ group were 5.03 ±0.07,5.17 ±0.10,5.46 ±0.10,5.68 ±0.15 and 5.83 ±0.11,respectively,which were significantly higher than those (4.49 ± 0.20,4.28 ± 0.13,4.45 ± 0.17,4.31 ±0.19 and 4.31 ±0.16) in control group (P＜0.01).Levels of FKN (pg/mL) in serum were 140.9 ± 15.8,157.9 ± 17.6,188.8 ± 24.8,224.4 ± 18.1 and 229.9 ± 10.0,respectively,significantly higher than those (121.7 ± 12.8,121.6 ± 12.1,118.3 ± 14.0,122.8 ± 12.4 and 120.5 ± 8.8) in control group (6 h P ＜0.05,others P ＜0.01).Levels of FKN (pg/mL) in lung tissue homogenate were 4 222.0 ± 641.1,5 021.0 ± 514.5,5 911.6 ± 478.1,7 092.2 ± 652.9 and 7 639.3 ± 666.6,respectively,significantly higher than those (2 860.2 ± 477.3,3 068.9 ± 446.0,3 168.7 ± 728.5,3 178.0 ±488.2 and 3 147.3 ±426.6) in control group (P ＜0.01).In PQ group,pathological changes manifested themselves in inflammatory cell infiltration,congestion,edema,structural damage,etc.The lung injury aggravated gradually from 6 h to 120 h.In control group,there was no significant change.FKN expressed mainly in bronchial cells,alveolar epithelial cells and pulmonary artery endothelial cells.Where there was higher expression of FKN,there were more inflammatory cells infiltrated.The level of FKN in lung tissue homogenate was positively correlated with lung coefficient (r =0.937).The level of FKN in serum was positively related to that in lung tissue homogenate (r =0.968).Conclusion There is correlation between FKN and acute lung injury induced by PQ in rats.