高原大鼠严重烧伤后氧化应激反应对小肠凋亡相关基因Bax,Bcl-2表达的影响

Influence of oxidative stress on expression of apoptosis-related gene Bax and Bcl-2 in severely scalded rats at plateau

目的:探讨高原大鼠严重烧伤延迟复苏后氧化应激反应对肠上皮细胞凋亡相关基因Bax和Bcl-2表达的影响.方法:将Wistar大鼠132只分为兰州组(1517 m)和高原组(3840 m),兰州组包括兰州即时复苏组(LIFR,n=30)、兰州延迟复苏组(LDFR,n=30)、假伤组(LCG,n=6),高原组包括高原即时复苏组(HIFR,n=30)、高原延迟复苏组(HDFR,n=30)、假伤组(HCG,n=30).大鼠背部30%TBSA(总体表面积)Ⅲ度烫伤后,立即或伤后6 h液体复苏.观察伤后肠黏膜中丙二醛(MDA)和总巯基(TSH)变化及凋亡相关基因Bax,Bcl-2表达变化.结果:高原地区MDA和TSH变化较兰州地区明显,免疫组化观察到伤后肠上皮Bax阳性细胞较兰州地区增多;HDFR组肠上皮Bax阳性表达早于LDFR组且更严重;MDA变化与肠上皮细胞Bax阳性表达成正相关(立即复苏组r=0.939,P<0.01;延迟复苏组r=0.938,P<0.05);TSH变化与肠上皮细胞Bax阳性表达成负相关(立即复苏组r=-0.949,P<0.01;延迟复苏组r=-0.934,P<0.01).Bcl-2基因表达高原地区均为阴性结果,兰州地区伤后6,12 h为阴性表达,其他情况为弱阳性表达.结论:高原大鼠烧伤延迟复苏后肠上皮细胞的严重氧化应激反应及Bax基因表达,可能是其凋亡增加的重要原因之一.

AIM： To explore the influence of oxidative stress on the expression of apoptosis-related gene Bax and Bcl-2 in severely scalded rats with delayed resuscitation at plateau. METHODS： A total of 132 Wistar rats were used as experimental models and were randomly divided into Lanzhou group and high altitude group. Lanzhou group （ altitude： 1517 m） consisted of immediate fluid resuscitation group （LIFR）, delayed fluid resuscitation group （LDFR） and control group （LCG）. The rats were subjected to 30% TBSA scald burn on the back and were given saline resus-citation immediately or 6 h later as delayed resuscitation. The rats in high altitude group （altitude： 3840 m） were divided in the same way as Lanzhou group but the groups were named respectively as HIFR, HDFR and HCG groups. The changes of the contents of intestinal malonaldehyde （MDA） and total hydro-sulfide （TSH） were determined to observe the oxidative stress of enteroeyte after burn. The expressions of Bax and Bcl-2 were detected by immunohistochemistry method. RESULTS： The levels of MDA increased and TSH decreased significantly in high altitude group than those in Lanzhou group. More Bax positive enteroeytes were observed in high altitude group compared with those in Lanzhou group. The positive expression of Bax in HDFR was higher than that in LDFR. A positive relationship existed between the levels of MDA and the Bax expression of enterocytess （IFR,r=0.939, P〈0.01; DFR,r=0.938, P〈0.01）. A negative relationship existed between the levels of TSH and the Bax expression of enterocytes （IFR, r = 0.949, P 〈 0.01 ; DFR, r=0.934, P 〈0. 01）. Bcl-2 gene was not observed in high altitude groups or 6 h and 12 h postburn in Lanzhou groups. A weak expression of Bel-2 was observed at other time point in Lanzhou groups. CONCLUSION： Serious oxidative stress and Bax expression of enterocytes may be causes of remarkable apoptosis of enteroeytes after burn and delayed resuscitation at plateau.