延迟复苏对烫伤大鼠肠道淋巴细胞凋亡率的影响

目的：探讨延迟复苏对烫伤大鼠小肠Peyer氏结淋巴细胞（PPL）、固有层淋巴细胞（LPL）和上皮内淋巴细胞（IEL）凋亡率的影响。方法：Wistar大鼠30只,分为假伤对照组、立即复苏组（ER）和延迟复苏组（DR）。建立30%体表面积Ⅲ度烫伤合并延迟复苏模型。按Davies法分离、收集上述3种淋巴细胞,采用DNA片段百分率（ap%）反映其伤后细胞凋亡百分率变化。采用DNA凝胶电泳、TUNEL法和电镜观察3种淋巴细胞凋亡特征性改变。结果：两组PPL、LPL、IEL伤后ap%均显著高于伤前（P〈0.01）;伤后6h、12h,DR组PPLap%显著高于ER组（P〈0.05或P〈0.01）,其中LPL伤后12hap%高达56.26%。伤后12hDR组LPL、IELap%显著高于ER组（P〈0.01）。伤后6hLPL、IEL基因组DNA电泳均可见凋亡特征性梯形条带;伤后12hTUNEL法和电镜均观察到3种淋巴细胞典型的凋亡形态学改变。结论：烫伤延迟复苏后细胞凋亡是肠道淋巴细胞数量急剧减少的主要原因;可能是烫伤后肠道免疫功能抑制的重要机制之一。

Influence of delayed resuscitation on the apoptosis of intestinal lymphocyte after scald in rats

Objective：To study the influence of delayed resuscitation on the apoptosis percentage of intestinal Peyer＇s patch lymphocytes （PPL） ,lamina propria lymphocytes （LPL） and intraepithelial lymphocytes （IEL） after burns with delayed resuscitation in rats. Methods： Twenty-four Wistar rats were divided into early resuscitation （ER） and delayed resuscitation （DR） groups, after being subjected to 30% TBSA Ⅲ degree scald burn on the back. Six rats with sham burn served as control. The lymphocytes were collected and separated by Davie＇s method. DNA fragmentation （ap % ） was applied to determine the apoptosis percentage of lymphocyte, DNA agarose gel electrophoresis,TUNEL method and electronic microscope （EM） were used to observe the specific apoptotie changes in intestinal lymphocytes, respectively. Results：The ap % of PPL, LPL and IEL increased significantly postburn （P〈0. 01）. The ap% of PPL in DR group was much higher than that in ER group at 6 and 12 hours postburn （P〈0.05 or P〈0.01） ,and the ap% of LPL was even as high as 56.26%. The ap% of LPL and IEL in DR group was much higher than that in ER group （P〈0.01）. Distinct DNA ladders were discerned in agarose gel electrophoresis of genome DNA of LPL and IEL at 6 hours postburn in two groups. Typical morphological changes of apoptosis were observed by TUNEL and EM in intestinal lymphocytes at 12 hours postburn. Conclusion： Apoptosis appears to be the major cause of dramatic cell loss of intestinal lymphoeytes after burn with delayed resuscitation, and might be one of the important mechanism underlying intestinal immunosuppression.