热应激反应对感染性休克大鼠肺损伤的影响

Effects of heat stress response on lung injury in septic shock rats

目的 研究热应激反应对感染性休克大鼠肺损伤的影响。方法 Ｗｉｓｔａｒ大鼠２４ 只随机分为三组。分别经肺动脉注射ＮＳ０．５ｍ ｌ（Ⅰ组）或内毒素（ＬＰＳ）１５ｍ ｇ·ｋｇ－ １ （Ⅱ组）或热应激处理１５ 分钟恢复２４ 小时后注射ＬＰＳ１５ｍ ｇ·ｋｇ－ １（Ⅲ组），然后取注射ＮＳ或ＬＰＳ前和后１、１．５、２、２．５、３、４ 小时末的动脉血分离血浆测定ＴＮＦ－α，同时用四导生理仪记录其平均肺动脉压（ｍ ＰＡＰ），平均动脉压（ＭＡＰ）、气道压（ＡＰ）、心率（ＨＲ）等血液动力学指标，并定期作血气分析测定动脉血氧分压（ＰａＯ２ ）。于４ 小时末活杀动物，取出肺脏称重，计算肺系数（ＬＣ）。结果 （１）Ⅱ、Ⅲ组动物注射ＬＰＳ后ＴＮＦ－α浓度明显升高，与Ⅰ组对比差异显著（Ｐ＜ ０．０５～０．０１），ＴＮＦ－α浓度于１．５～２ 小时达到峰值，２ 小时后开始下降，４ 小时基本恢复至基础值，其中Ⅲ组ＴＮＦ－α浓度明显低于Ⅱ组各相应时间点ＴＮＦ－α浓度值（Ｐ＜ ０．０５）；（２）Ⅱ、Ⅲ组动物于注射ＬＰＳ０．５ 小时后ＭＡＰ、ＰａＯ２ 开始明显下降，ｍ ＰＡＰ、ＡＰ、ＨＲ明显上升，与Ⅰ组比较差异显著（Ｐ＜ ０．０５～０．０１），Ⅱ组变化值较Ⅲ组相应时间点?

Objective To investigate the effects of heat shock response(HSR)on arterial tumor necrosis factor α (TNF α) concentration,lung fluid content,arterial oxygen tension(PaO 2) and hemodynamics in septic shock.Methods Twenty four Wistar rats were randomly divided into three groups.Normal saline 0 5ml (groupⅠ),LPS 15mg/kg(groupⅡ),or LPS 15mg/kg 24h after HSR(group Ⅲ) were administered through pulmonary artery catheter.The carotic arterial samples were drawn before and 1,1 5,2,2 5,3 and 4h after the administration,to measure the TNF α concentration.MAP,mean pulmonary pressure(mPAP),airway pressure(AP),HR and PaO 2 were also recorded.The rats were killed 4 hours after the administration to measure the weight of wet lungs and calculate lung coefficient(LC).Results (1)TNF α levels in groupⅡ and Ⅲ increased significantly after LPS injection(P<0.05),reached the peak level 1.5 2h later,then dropped and returned to the baseline 4 h after LPS injection.TNF α levels in groupⅡ were higher than those in groupⅢ at each time point(P<0.05).(2)MAP and PaO 2 decreased and mPAP,AP and HR increased more significanly in groupⅡ than those in groupⅢ at all time point(P<0.05).(3)LC was higher in groupⅡ and Ⅲ than that in groupⅠ,and the level in groupⅡ was the highest among the three groups (P<0.05).(4)There were remarkable correlations between TNF α level and mPAP,MAP,AP,PaO 2 or LC(r=0 953,-0.879,0.953,0.764,-0.628,0.792,respectively).Conclusion HSR can decrease the arterial concentration of TNF α,improve hemodynamics and PaO 2,and lower the pulmonary fluid content in septic shock rats,indicating that HSR may protect septic rats lung from injuries.