选择性肠道去污染对创伤性截瘫家兔小肠组织MDA含量和SOD、GSH-Px的影响

摘要

Objective To explore effects of selective digestive decontamination(SDD)on the content of malondialdehyde(MDA),superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px),and its effects on oxi-dative stress reaction in small intestinal mucosa in paraplegic rabbits.Methods Forty rabbits were subjected to a complete paraplegia following spinal cord injury,and divided into SDD-treated(n=20)and control groups(n=20). The treatment group received SDD using PTA(polymyxin,tobramycin and amphotericin B)protocol by gavage three times daily for 4d after injury.The control group was given the same amount of normal saline.Samples from the small intestine were collected to detect MDA content,SOD and GSH-Px activities and to assess morphological chan-ges in the small intestine,using Hematoxylin and eosin staining.The correlation between MDA,SOD and GSH-Px levels and the degree of intestinal mucosal damage were analysed.Results The content of MDA[(3.58 ±0.98) nmol/mgprot vs.(8.19 ±1.22)nmoL/mgprot,P<0.001]in intestinal tissue was significantly lower in the SDD group than those in the control group(P<0.001).The activities of SOD[(57.2 ±9.4)U/mgport vs.(42.7 ± 13.4)U/mgport]and GSH-Px[(111.6 ±12.0)U/mgport vs.(89.7 ±11.0)U/mgport]were obviously higher in the SDD group than those in the control group.Correlation alalysis showed a positive correlation between MDA con-tent and degree of intestinal mucosal damage(P<0.001,r=0.649),and a negative relation between SOD(r=-0.387),GSH-Px(r=-0.531)activities and degree of intestinal mucosal injury(P<0.001).Conclusion SDD protects against lipid peroxidation in intestinal tissues and reduces oxidative stress damage in rabbits with com -plete paraplegia.%目的 探讨选择性肠道去污染(selective decontamination of the digestive tract,SDD)对创伤性截瘫家兔肠道组织丙二醛(malondialdehyde,MDA)含量和超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧物酶(glutathione peroxidase,GSH-Px)的影响,明确SDD对截瘫家兔肠道氧化应激损伤的保护作用.方法 建立截瘫家兔模型.选择40只体质量为2.0~2.5kg 6月龄清洁级健康家兔,雌雄不限,随机分为处理组和对照组,每组20只;另外增加正常对照组家兔10只.采用PTA方案[多粘菌素E(P)、妥布霉素(T)和两性霉素B(A)]进行SDD处理4d.4d后处死家兔,采集距回盲部5cm左右小肠标本进行HE染色观察小肠黏膜变化,并检测小肠组织MDA含量和SOD、GSH-Px水平.结果 SDD处理组小肠组织MDA水平较对照组明显降低[(3.58 ±0.98)nmoL/mgprot vs.(8.19 ±1.22)nmoL/mgprot,P<0.001];处理组SOD活性明显高于对照组[(57.2 ±9.4)U/mgport vs.(42.7 ±13.4)U/mgport,P<0.001];处理组GSH-Px活性也明显高于对照组[(111.6 ±12.0)U/mgport vs.(89.7 ±11.0)U/mgport,P<0.001].相关分析表明,小肠HE染色Chiu病理评分与小肠组织MDA含量呈显著正相关(P<0.001,r=0.649),与SOD(r=-0.387)、GSH-Px(r=-0.531)活性呈显著负相关(P<0.001).结论 SDD处理截瘫家兔后可减弱肠道脂质过氧化反应,减轻氧化应激损伤,从而保护肠黏膜.