一氧化碳对内毒素血症肠道细胞凋亡的影响

The effects of carbon monoxide on apoptosis of intestinal cells in endotoxemia

目的探讨外源性一氧化碳对内毒素血症大鼠肠道细胞凋亡的影响及作用机制。方法以血气分析仪监测大鼠血气参数,对空白组、内毒素组(5mg/kg)、低体积分数CO吸入组(250×10-6)、腹腔内CO注射组(2ml/kg),内毒素(5mg/kg)+CO吸入组(250ppm)以及内毒素(5mg/kg)+腹腔内注射CO组(250×10-6)组,分别在1、3、6h时间点上,用硫代巴比妥酸法(TBA法)测定肠道丙二醛(MDA)含量,用羟胺法测定超氧化物歧化酶(SOD)活性,并应用流式细胞仪对肠道细胞的凋亡率进行检测,进行统计学分析。同时通过HE染色观察3h时间点上的肠道病理变化。结果吸入250×10-6的CO以及腹腔内注射2ml/kg的CO,没有造成大鼠的缺氧,而外源性的CO降低了内毒素血症时大鼠肠道组织中的MDA含量,同时提高了SOD的活性,肠组织细胞的凋亡率降低。对肠细胞凋亡的影响,腹腔内注射组CO的作用早于CO吸入组,而持续吸入组抗凋亡作用维持时间较长。结论低体积分数的CO(250×10-6)吸入和一次性腹腔内注射CO(2ml/kg)对大鼠是安全的,补充外源性的CO可以对内毒素血症大鼠肠道损伤提供保护作用,抑制肠道细胞的凋亡,保护肠道免受内毒素导致的进一步损伤。腹腔内注射CO对内毒素肠道细胞凋亡的影响早于CO吸入对肠道细胞的影响,但一次性给气维持时间较短。

Objective To study the effects and the mechanism of exogenous carbon monoxide on apoptosis of rat intestinal cells during endotoxemia. Methods The experimental rats were divided into 6 groups： control group, LPS （lipopolysaccharide： 5 mg/kg） group, CO inhalation （250 × 10^-6） group, CO intraperitoneal injection （2 ml/kg） group, LPS （LPS 5 mg/kg） with CO inhalation （250 ×10^-6 ） group and LPS （LPS 5 mg/kg） with CO intraperitoneal injection （2 ml/kg） group. The PaO2 , PaCO2 , SO2 and COHb were monitored by blood gas analysis. The rat intestine malondialdehyde （MDA） was determined by thiobarbitric acid method and superoxide dismutase （SOD） was determined by hydroxylamine method after the rats were treated for 1, 3 and 6 hours. We also checked the apoptosis ratio of intestinal cells with flow cytometry （FCM）. We also monitored the pathological changes with HE staining. Results Low concentration CO （250 × 10^-6） inhalation and CO intraperitoneal injection （2 ml/kg） did not cause hypoxia. Comparing to control group and endotoxemia group, the intestineal MDA of the endotoxemic rats decreased after exposure to exogenous CO and the SOD activation increased. The apoptosis ratio of intestinal cells decreased after exposure to exogenous CO. On the apoptosis of endotoxemia rat intestinal cells, the effect of CO intraperitoneal injection was earlier than that of CO inhalation, but the effect of CO inhalation last longer. Conclusion Low concentration CO （250 × 10^-6 ） inhalation and low dose CO （2 ml/ kg） intraperitoneal injection were safe to rat. Exposure to exogenous CO could protect rat intestine against endotoxemia by inhibiting the apoptosis of intestinal cells. The effect of intraperitoneal CO injection was earlier than that of CO inhalation, but the effect of CO inhalation could last for longer than intraperitoneal CO injection.