高原地区大鼠烫伤延迟复苏后Peyer氏结中Bax表达与T细胞凋亡和增殖的关系

Relationship between Bax expression and the apoptosis as well as proliferation of T cells in the Peyer's patches after burns with delayed fluid resuscitation at different altitude in rats

目的:探讨不同海拔高度大鼠烫伤延迟复苏后回肠Peyer氏结中淋巴细胞凋亡率和促凋亡基因Bax与T细胞增殖的变化及意义。方法:Wistar大鼠132只,分别在1517m和3848m两个海拔高度随机分为延迟复苏组(DFR,n=30)、即时复苏组(IFR,n=30)和假伤组(SG,n=6),建立30%TBSAⅢ度烫伤模型,分别于伤后6、12、24、48和72h在回盲部向近心端10cm处切取回肠组织后,于肠壁上切取所有Peyer氏结,采用TUNEL、免疫组织化学染色与图像分析技术,观察回肠Peyer氏结中淋巴细胞凋亡率的变化、Bax和CD3+的表达。结果:各海拔高度DFR组凋亡率均高于IFR组,各复苏组伤后12h凋亡率最高;Bax的阳性表达位于Peyer氏结中淋巴细胞胞浆内,其表达强度各复苏组高于假伤组,随海拔高度上升Bax表达增强,高海拔组的表达强度高于低海拔组,各海拔高度DFR高于IFR组(P<0·05);CD3+的阳性表达部位位于Peyer氏结中T淋巴细胞胞膜,其表达强度各复苏组低于假伤组,随海拔高度上升CD3+表达减弱,伤后12h表达降至最低(P<0·05)。结论:高原地区烫伤延迟复苏后Bax表达增高可能是Peyer氏结T淋巴细胞凋亡率增加和T淋巴细胞数降低的重要原因之一。

Objective：To investigate the changes in Bax and CD^3＋ expression as well as the apoptotic rate of T cells in the Peyefs patches after severe burn with delayed fluid resuscitation at different altitude in rats. Methods： One hundred and thirty-two Wistar rats were randomly divided into three groups at 1 517 meters and 3 848 meters altitude respectively： delayed fluid resuscitation group （DFR）, immediate fluid resuscitation group （IFR） and sham group （SG）. Rats in DFR and IFR were inflicted 30 % TBSA full-thickness scald injury. The Peyer＇s patches were harvested from the ileum of rats at 6, 12, 24, 48 and 72 hours after burns respectively. The levels of Bax and CD^3＋ expression and the rate of apoptosis in Peyefs patches were detected by TUNEL,tissue microarray technology and immunohistochemistry. Results：The apoptotic rate in Peyer＇s patches were higher in DFR group than those in IFR group at the two altitude, and it reached the peak value at 12 hours at each altitude. The increase in Bax expression was observed mainly in lymphocytes. The expression levels of Bax in Peyer＇s patches were much higher in DFR group and IFR group than those in SG and higher at 3 848 meters altitude than those at 1 517 meters, and higher in DFR group than those in IFR group（P〈0.05）. The decrease in CD^3＋ expression was observed mainly on cell membrane in T lymphocytes. The expression levels of CD^3＋ in Peyer＇s patches were much lower in DFR group and IFR group than those in SG group, the trough value at 12 hours after burns（P〈0. 05）. Conclusion： High expression of Bax might be reponsihle for the high apoptotic rate and decrease in T lymphocytes numbers in Peyer＇s patches after severe burn with delayed fluid resuscitation at different altitude in rats.