亚甲蓝对兔肠缺血再灌注时肺损伤的影响

Effects of methylene blue on lung injury in rabbits after intestinal ischemia reperfusion

目的评价亚甲蓝（MB）对兔肠缺血再灌注时肺损伤的影响。方法健康新西兰白兔36只,体重2.5～3.5 kg,雄雌不拘,随机分为3组（n=12）,假手术组（S组）不夹闭肠系膜上动脉;缺血再灌注组（I/R组）：夹闭肠系膜上动脉1 h,再灌注3 h;MB组再灌注前即刻静脉注射亚甲蓝10 mg/kg。再灌注3 h时,抽取静脉血,测定血清肿瘤坏死因子-α（TNF-α）、白细胞介素-8（IL-8）及总蛋白浓度;取右肺下叶组织,测定肺组织湿/干重比（W/D）和Na^＋-K^＋-ATPase活性;测定支气管肺泡灌洗液（BALF）中蛋白浓度,并计算其与血清总蛋白浓度的比值,表示肺通透指数;光镜及电镜下观察肺组织结构,并进行中性粒细胞（PMN）计数。结果与S组比较,I/R组血清TNF-α、IL-8浓度及BALF蛋白浓度、PMN计数、肺通透指数和W/D升高,Na^＋-K^＋-ATPase活性降低,MB组PMN计数、BALF蛋白浓度和肺通透指数升高,Na^＋-K^＋-ATPase活性降低（P〈0.05或0.01）;与I/R组比较,MB组血清TNF-α、IL-8及BALF蛋白浓度、PMN计数、肺通透指数和W/D降低,Na^＋-K^＋-ATPase活性升高（P〈0.05或0.01）。MB组肺组织结构损伤轻于I/R组。结论再灌注前即刻静脉注射亚甲蓝10 mg/kg可减轻兔肠缺血再灌注时肺损伤,与抑制肺组织Na^＋-K^＋-ATPase活性降低及减轻炎性反应有关。

Objective To investigate the effects of methylene blue（MB）on lung injury in rabbits after intestinal ischemia reperfusion.Methods Thirty-six rabbits were divided into three groups（n=12 each）：sham operated group（group S）underwent an identical laparotomy except for the superior mesenteric artery（SMA） occlusion.The I/R group and MB treated group was produced by occluding the SMA for 1 h,reperfusing for 3 h respectively.MB group was received 1% MB by 10 mg/kg before immediately removed the clip,I/R group was administered with saline.Reperfusion was confirmed by the return of pulsation to the mesenteric arcade.Three hours after reperfusion,the animals were killed.Lung wet-weight to dry-weight ratio was stand for lung total liquid, the serum IL-8,TNF-αconcentration and lung tissue Na^＋-K^＋-ATPase activity were measured.The protein concentration of serum to bronchoalveolar lavage fluid（BALF）ratio was measured and stand for lung permeability index.Pathological histology studied of lung were carried out.Results The serum concentration of IL-8,TNF-α, PMN count,BALF protein concentration,lung permeability index,and lung W/D ratio were significantly higher and Na^＋-K^＋-ATPase activity was lower in group I/R than in group S.The PMN count,BALF protein concentration,lung permeability index were higher and Na^＋-K^＋-ATPase activity was lower in group MB than in group S.The serum concentration of IL-8,TNF-α,PMN count,BALF protein concentration,lung permeability index,and lung W/D ratio were significantly lower and Na^＋-K^＋ -ATPase activity was higher in group MB than in group I/R.Pathological injury of lung in MB group was lightly change compared to S group.Conclusion MB 10 mg/kgⅣbefore reperfusion can lighten lung injury in rabbits after intestinal ischemia reperfusion by preventing Na^＋-K^＋-ATPase activity further decreasing and decreasing inflammatory response.