【作者】 张扬；

【导师】 高巨；

【作者基本信息】 扬州大学 ， 麻醉学（专业学位）， 2016， 硕士

【摘要】 目的通过建立大鼠内毒素所致肺损伤模型,探讨小潮气量机械通气预处理对大鼠内毒素所致急性肺损伤的影响,并阐明其可能相关机制。方法成年雄性S-D大鼠48只,8-12周龄,体重250-300 g,采取随机数字表法,将其分为4组(n=12):sham组：腹腔注射0.9%生理盐水0.5ml; MV-saline组：先进行机械通气预处理1h,通气结束后予以0.9%生理盐水0.5ml腹腔注射；LPS组：大鼠腹腔注射脂多糖(LPS)溶液0.5ml; MV-LPS组：先进行机械通气预处理1h,通气结束后予以LPS溶液0.5ml腹腔注射。所有大鼠术前均采用2%戊巴比妥钠腹腔注射麻醉,术中机械通气参数设置均为潮气量6 ml/kg、PEEP=0mmHg、频率40次／分、I：E=1：2、吸入气体为空气,术中腹腔注射的LPS溶液的剂量均为40 mg/kg。所有动物在完成腹腔注射6h后,统一放血处死并收集组织标本。取肺组织后,测定肺组织湿／干重比(W/D比)、伊文思蓝染料渗透率,观察肺组织病理学改变,行肺损伤评分。使用ELISA法测定支气管肺泡灌洗液(BALF)中肿瘤坏死因子(TNF)-α、白介素(IL)-1β及IL-6的浓度,使用TUNEL染色法测定肺组织细胞凋亡指数(AI)、使用免疫组织化学和Western bolt方法测定肺组织中ROCK1蛋白的表达,使用RT-PCR法测定肺组织中RhoA mRNA、ROCK2 mRNA的表达。结果与sham组比较,LPS组、MV-LPS组大鼠肺组织损伤评分、W/D比值、AI值、肺组织伊文思蓝染料渗透率及BALF中炎症因子TNF-α、IL-1β、IL-6的浓度明显升高(P<0.05)；与sham组比较,LPS组、MV-LPS组大鼠肺组织中RhoA mRNA、ROCK2 mRNA及ROCK1蛋白的表达明显上调(P<0.05)；与LPS组比较,MV-LPS组大鼠肺组织损伤评分、W/D比值、AI值、肺组织伊文思蓝染料渗透率及BALF中炎症因子TNF-α、IL-1β、IL-6浓度明显下降(P<0.05)；与LPS组比较,MV-LPS组大鼠肺组织中RhoA mRNA、 ROCK2 mRNA及ROCK1蛋白的表达也明显下调(P<0.05)。结论LPS腹腔注射可导致大鼠严重的急性肺损伤,小潮气量机械通气预处理能够有效减轻LPS引起的急性肺损伤,其早期的保护效应可能与抑制RhoA/ROCK通路有关。更多还原

【Abstract】 Objective Effects of low tidal volume (LTV) ventilation preconditioning in endotoxin-induced acute lung injury (ALI) have not been studied. We investigated the effect of LTV ventilation pretreatment on ALI induced by lipopolysaccharide (LPS) in rats.Methods Forty-eight healthy male SD rats, weighing 250-300g,8-12 weeks, were randomly divided into 4 groups(n=12 each):(i) sham rats injected (i.p.) with 0.5m10.9% (physiologic) saline; sham rats pretreated with tidal volume 6 mL/kg ventilation for 1 h followed by injection (i.p.) of 0.5mlphysiologic saline (MV-saline group); (ⅲ) rats injected with LPS (i.p.) 40 mg/kg dissolved in 0.5 ml saline (LPS group); rats pretreated with tidal volume 6 mL/kg ventilation for 1 h before injection (i.p.) with LPS (MV-LPS group). Animals were observed for 6 h and sacrificed.Tumor necrosis factor(TNF)-a, interleukin(IL)-1β and IL-6 concentrations in bronchoalveolar lavage fluid(BALF)were determined(by ELISA). Lungs were removed formeasurement of lung wet-to-dry ratio (W/D ratio), Evans Blue Dye extravasation, microscopic examination and the lung injury was scored. Lung tissue cell apoptosis was also determined (by TUNEL) and the apoptosis index (AI) was calculated, the expression of pulmonary RhoA, ROCK2 mRNA(by RT-PCR), and ROCK1 protein (by Immunohistochemical staining and Western blot method) in lung alveolar cells were determined.Results Compared with sham group,the lung injury score, W/D ratio,AI,extravasation of Evans Blue Dyein alveolar and a variety of inflammatory cytokines, like TNF-a,IL-1β and IL-6were significantly increased in LPS group and MV-LPS group(P<0.05), and expression of pulmonary RhoA, ROCK2 mRNA, and ROCK1 protein were also up-regulated(P<0.05); compared withLPS group.the lung injury score, W/D ratio,AI,extravasation of Evans Blue Dye in alveolar and a variety of inflammatory cytokines, like TNF-a,IL-1β and IL-6 were significantlydecreased in MV-LPS group(P<0.05), and expression of pulmonary RhoA, ROCK2 mRNA, and ROCK1 protein were also reduced(P<0.05).Conclusion LPS could caused severe ALI,LTV ventilation preconditioning can attenuate release of pulmonary pro-inflammatory cytokines and decrease the AI induced by severe sepsis. Early protection seems to be mediated partly through inhibition of activation of a Rho pathway.更多还原