氧自由基对烫伤大鼠延迟复苏后肠上皮细胞凋亡的影响

目的：观察烧伤延迟复苏后肠粘膜上皮细胞凋亡的发生规律及与氧自由基损伤的关系。方法：１５０只雄性Ｗｉｓｔａｒ大鼠随机分为Ａ组（烫伤立即复苏组，ｎ＝６０）、Ｂ组（烫伤延迟复苏组，ｎ＝５０）、Ｃ组（Ｎ－乙酰半胱氨酸（ＮＡＣ）治疗组，ｎ＝２０）和Ｄ组（别嘌呤醇治疗组，ｎ＝２０）。３０％总体表面积（ＴＢＳＡ）Ⅲ度烫伤大鼠伤后６小时进行复苏。观察伤后肠粘膜上皮细胞凋亡发生规律，测定Ａ、Ｂ组伤后３、６、１２、２

The influence of oxygen free radical on enterocyte apoptosis in scald rats after delayed resuscitation

Objective:To observe the occurrence of enterocyte apoptosis in scald rats after delayed resuscitation and its relationship with oxygen free radical (OFR) injury.Methods:One hundred and fifty male Wistar rats were randomly divided into four groups:group A,prompt resuscitation (n=60);group B,delayed resuscitation (n=50);group C,Nacetylcysteine (NAC) treatment (n=20);group D,allopurinol treatment (n=20).Animals were subjected to 30% total body surface area fullthickness scald,followed by delayed resuscitation.Apoptosis of enterocytes was identified by DNA fragmentation (ap%) detection,DNA agarose gel electrophoresis and terminal deoxynucleotidyltransferase mediated dUTPbiotin nick end labeling(TUNEL),histochemistry methods.The contents of malondialdehyde (MDA),total thiol (TSH),nonprotein thiol (NPSH) and the activity of xanthine oxidase(XO) in intestinal mucosa were determined at different time points postburn.Results:The ap% of intestinal epithelial cells significantly increased in groups A and B,peaking at 12 hours in groups A and B.The increased ap% in group B occurred much earlier and higher than in group A from 3 to 48 hours postburn(P<0 05 or P<0 01).This was corroborated by the results observed in electrophoresis and TUNEL method.The levels of intestinal MDA and XO dramatically increased,but the contents of intestinal TSH and NPSH significantly decreased postburn in groups A and B.The levels of ap% and MDA in group C were much lower compared with group B,but that of NPSH was higher in group C.The activity of XO significantly decreased,but no significant change in ap% was observed in group D,compared with group B.There was a significant positive correlation between the intestinal ap% and the content of MDA in group B,but for the change in NPSH,the correlation was negative.Conclusions:Significant apoptosis of enterocytes is induced by delayed resuscitation after scald in rats.A close correlation exists between apoptosis and the oxygen stress in intestinal mucosa.NAC treatment can blunt intestinal apoptosis induced by OFR which is generated by the process of ischemiareperfusion after burn injury.