维生素C对烫伤休克大鼠肠内补液时肠组织氧自由基损伤的影响

Vitamin C alleviates oxygen free radical injury in the gut during enteral rehydration of burn shock in rats

目的研究维生素C对烫伤休克大鼠肠内补液时肠组织氧自由基损伤的影响。方法雄性Wistar大鼠40只,20%乌拉坦(100mg/kg)肌注麻醉后,采用沸水法(100℃,15s)造成35% TBSA Ⅲ度烫伤,行十二指肠和空肠置管。随机分为单烫组(S组)、葡萄糖-电解质溶液(GES)组、VC组和GES/VC组,每组10只,GES组和GES/VC组大鼠在烫伤后30min将GES经十二指肠置管处匀速泵入,前4h按1/2Parkland公式量和速率(2ml.1%TBSA-1.kg-1)补液,VC组和GES/VC组大鼠在伤后30min将VC(250mg/kg)单独或溶于GES中注入十二指肠。伤后4h处死大鼠,取空肠组织测定丙二醛(MDA)含量及黄嘌呤氧化酶(XOD)、髓过氧化物酶(MPO)活性,并用干湿重法测定肠组织含水率(GW)。结果与S组比较,GES组MDA含量明显增高(P<0.05),而XOD、MPO活性两组比较无显著差异;VC组和GES/VC组上述指标与S组和GES组比较均显著降低(P<0.05)。GES组GW(83.1%±2.4%)显著高于S组(78.8%±2.5%,P<0.05),且二者均明显高于VC组(72.4%±1.2%)和GES/VC组(68.9%±2.1%,P<0.05)。结论VC能减轻烫伤休克大鼠肠内补液时的缺血再灌注损伤和肠组织水肿。

Objective To investigate the effect of Vitamin C （VC） on oxygen free radical injuries in gut during enteral rehydration of burn shock. Method Forty male Wistar rats were subjected to a 35% TBSA full thickness scald injury and randomly divided into four groups： scald with no rehydration （S, n= 10）, scald with enteral infusion either of a glucose electrolyte solution （GES, n= 10） or GES containing VC （250mg/kg, GES/VC, n=10）, and scald with enteral administration of VC alone （VC, n=10）. The GES was introduced into intestine through a duodenal stoma in an amount in accordance with Parkland formula （2ml · 1% TBSA^-1 · kg^-1 ） 30 minutes after scald, and VC （250mg/kg） was administered simultaneously through the same path. Four hours after injury, all rats were sacrificed and the specimens of jejunum were harvested for evaluation of xanthine oxidase （XOD）, malondialdehyde （MDA） and myeloperoxidase （MPO）, and intestine water content was determined with ratio of dry to wet weight. Results GES rehydration led to a 17.5% increase in XOD activity compared with that of S group （P〈0. 05）. Similar results were obtained in assessing MPO （30. 1%） and MDA （20.4%, P %0. 05）. GES/VC rehydration resulted in markedly lower levels of XOD （1. 974±0. 311 vs 2. 630±0. 648, P〈0. 05）, MPO （0. 759± 0. 235 vs 0. 812±0. 136, P〈0. 05） and MDA （0. 116±0. 013 vs 0. 589±0. 095, P〈0. 05） compared with those of GES. The lowest results of all parameters were observed in VC group among the four groups. Intestinal water content in GES group （83. 1%±2. 4%） was higher than that in S group （78. 8 % ± 2. 5 %, P〈0.05 ）. Intestinal water contents in VC and GES/VC groups （72. 4% ± 1.2% and 68. 9%±2. 1%） were lower than those in S and GES groups （P〈0. 05）. Conclusion The results indicate that VC may alleviate gut ische mia reperfusion injury and mucosa edema in enteral hydration after scalded shock.