过氧化物酶增殖体激活受体-γ激动剂对急性肺损伤大鼠的保护作用及机制

目的 观察过氧化物酶增殖体激活受体-γ(PPAR-γ)激动剂对急性肺损伤大鼠的保护作用及其机制.方法 将72只Wistar大鼠按随机数字表法分为脂多糖组(32只)、曲格列酮干预组(32只)和对照组(8只).脂多糖组和曲格列酮干预组根据检测时间的不同再分为脂多糖及曲格列酮干预1、2、4、8 h组,每组各8只.脂多糖组静脉给予脂多糖(5 mg/kg),曲格列酮干预组在静脉注射脂多糖15 min后静脉给予曲格列酮(3 mg/kg).观察各组大鼠PaO2、肺组织髓过氧化物酶(MPO)活性、肺组织病理;采用RT-PCR法检测肺组织PPAR-γ、肿瘤坏死因子-γ(TNF-γ)mRNA表达;采用酶联免疫吸附法(ELISA)检测TNF-γ蛋白变化及用免疫组织化学观察肺组织PPAR-γ的改变;采用Western blot法测定肺组织核因子-γB(NF-γB)P65活性.采用SPSS 10.0软件进行统计学分析,各组间均数比较采用方差分析,均数两两比较采用q检验.结果 曲格列酮1、2、4、8 h组PaO2分别为(85±10)、(80±10)、(81±10)、(82±13)mm Hg(1 mm Hg=0.133 kPa),脂多糖组1、2.4、8 h组分别为(75±11)、(69±12)、(63±11)、(71±13)mm Hg,两组比较差异有统计学意义(F=4.32,P＜0.05);脂多糖2.4、8 h组MPO活性分别为(10.6±1.2)、(14.1±2.1)、(11.1±1.8)U/g,曲格列酮2、4、8 h组分别为(8.2±0.8)、(9.2±0.9)、(8.8±0.7)U/g,两组比较差异有统计学意义(F=14.99,P＜0.05);脂多糖1、2 h组肺组织TNF-γmRNA吸光度(A)值分别为0.68±0.07、0.92 ±0.05,曲格列酮1、2 h组分别为0.39±0.07、0.50±0.09,两组比较差异有统计学意义(q值分别为3.09、3.99,P＜0.05);脂多糖1、2 h组肺组织匀浆及血浆中TNF-?水平分别为(340±33)、(757±47)、(12.3±1.8)及(54.7±6.6)ng/L,曲格列酮1、2 h组为(306±30)、(685±47)、(10.0±1.7)及(46.8±5.9)ng/L,两组比较差异有统计学意义(q值分别为3.92、4.71、4.81、5.17,均P＜0.05);脂多糖1、2、4 h组肺组织PPAR-? mRNA表达(A值)分别为0.36±0.05、0.25±0.04、0.30±0.05,曲格列酮1、2.4 h干预组分别为0.39±0.02、0.44±0.05、0.46±0.04,两组比较差异有统计学意义(q值分别为6.13、5.69、3.72,均P＜0.05);脂多糖1、8 h组NF-?B P65由胞质向胞核移位(A值分别为0.81±0.14、1.91±0.16、0.33±0.06及2.01±0.18),曲格列酮1、8 h组分别为1.14±0.15、1.06±0.21、0.81±0.14、1.03±0.18,两组比较差异有统计学意义(q值分别为3.29、6.25、5.59、6.81,均P＜0.05).结论 在脂多糖诱发的大鼠急性肺损伤模型中,曲格列酮通过上调PPAR-γ表达来抑制NF-γB活性,使NF-γB调控的炎症介质表达下调,炎性细胞浸润和活化减少,从而保护肺组织.

The protective effects and mechanisms of peroxisome proliferator-activated receptor-γ agonist in rats with acute lung injury

Objective To observe if peroxisome proliferator-activated receptor-γ/(PPAR-γ)agonist (troglitazone) was able to alleviate lipopolysaccharide (LPS) -induced acute lung injury (ALI) in rats,and explore the underlying mechanisms.Methods Seventy-two wistar rats were randomized into the the following groups,the LPS groups (32 rats),and the troglitazone intervention groups(T group,32 rats)and a control group (8 rats).T groups and LPS groups were divided into 1,2,4,8 h subgroups(n=8 each)according to the experimental protocol.LPS(5 mg/kg) was administered through the vein in the LPS groups.In the T groups,15 min after LPS injecting,troglitazone was administrated (3 mg/kg) through the vein.PaO2,myeloperoxidase activity (MPO),lung tissue histopathological changes were observed. Expressions of expression of PPAR-γ protein in lung tissue detected by immunohischemistry method,and expression of 10.0 software.Results PaO2 in 1,2,4,and 8 h groups were (85±0),(80±0),(81±0),(82±13)mm Hg(1 mm Hg=0.133 kPa)in the T groups,(75±1),(69±2),(63±1),(71±3)mm Hg in the LPS groups,respectively,the difference being significant between groups(F=4.32,P＜0.05).MPO aetivity in 2,4 and 8 h groups were(10.6±1.2),(14.1±2.1),(11.1±1.8)U/g in the LPS groups,(8.2±0.8),(9.2±0.9),(8.8±0.7)U/g in the T groups,and comparison between groups showed statistical significance (F=14.99,P＜0.05).TNF-γmRNA expression (A) in 1 h group and 2 h group were 0.68±.07,0.92±.05 in the LPS groups and 0.39±.07,0.50±.09 in the T groups,and comparison between groups showed statistical significance (q=3.09,3.99,P＜0.05).TNF-γ levels in 1 h group and 2 h group in lung homogenate and plasma were (340±3),(757±7),(12.3±1.8),(54.7±.6)ng/L in LPS groups,(306±30),(685±47),(10.0±1.7),(46.8±5.9)ng/L in T groups,the difference between groups being significant (q=3.92,4.71,4.81,5.17,all P＜0.05).PPAR-γmRNA expression(A) in 1 h,2 h and 4 h groups were 0.36±.05,0.25±.04,0.30±.05 in the LPS groups,0.39±.02,0.44±.05,0.46±.04 in the T groups,the difference between groups being significant (q=6.13,5.69,3.72,all P＜0.05).NF-γB P65 translocated from plasma to nucleus in 1 h and 8 h group;the A values were 0.81±.14,1.91±.16,0.33±.06,2.01±.18 in the LPS groups and 1.14±.15,1.06±.21,0.81±.14,1.03±.18 in the T groups,comparison between groups showed statistical difference (q=3.29,6.25,5.59,6.81,all P＜0.05).Conclusion PPAR-γagonist (troglitazone) decreased the expression levels of inflammatory mediators such as TNF-γ,reduced infiltration and activation of inflammatory cells in lung tissues,and alleviated LPS-induced through PPAR-γupregnlation and inhibition of NF-γB activity.