小肠集合淋巴结细胞凋亡对严重烫伤小鼠肠道免疫屏障的影响

目的观察严重烫伤小鼠小肠集合淋巴结(Peyer patches,PP结)细胞凋亡的变化规律,探讨其在肠黏膜免疫屏障功能障碍中的作用。方法将40只BALB／c小鼠随机分为正常对照组及烫伤后12、24、72 h组,每组10只。各致伤组小鼠背部造成20％TBSAⅢ度烫伤后,按时相点处死并留取全部PP结。对照组小鼠处死后亦留取相同标本。分别行HE染色、DNA琼脂糖凝胶电泳,标记PP结细胞作流式细胞仪(FCM)检测。结果HE染色见烫伤小鼠PP结生发中心有大量淋巴细胞凋亡。DNA琼脂糖凝胶电泳显示烫伤组各时相点有“梯形”条带。FCM结果显示对照组和烫伤各组PP结细胞凋亡率分别为(4．9±2．1)％、(26．7±3．1)％、(21．6±4．0)％、(12．8±2．0)％,伤后12 h为峰值。结论严重烫伤小鼠PP结淋巴细胞早期凋亡为细胞的主要死亡模式,在严重烫伤后早期肠黏膜免疫屏障功能损伤中起重要作用。

The influence of apoptosis of lymphocytes of Peyer's patches on the pathogenesis of gut barrier damage in severely scalded mice

OBJECTIVE: To investigate the changes in cellular apoptosis of Peyer's patches in severely scalded mice, and to explore its role in the pathogenesis of gut barrier damage. METHODS: Forty BALB/c mice were randomly divided into normal control, 12 post-scald hour (12PSH), 24PSH and 72PSH groups, with 10 in each group. The mice in all PSH groups were inflicted with 20% TBSA full-thickness scald on the back. The mice in all the groups were sacrificed at different time points, and Peyer's patches were harvested from all the mice for HE staining, DNA gel electrophoresis, and flow cytometry ( FCM) examination with FITC conjuated Annexin-v and propiddium iodidc( PI) staining of cells. RESULTS: HE staining revealed that there were relatively abundant apoptotic cells scattering in Peyer's patches of scalded mice . DNA electrophoresis of Peyer's patches revealed typical " ladder" pattern at all indicated time points in scalded mice. Apoptotic percentage of detached Peyer's patche cells in control and scalded group were (4. 9+/-2. 1)% , (26.7+/-3. 1)% , (21.6 +/-4.0)% ,(12. 8 +/-2.0)% , respectively, and the percentage reached the peak at 12 PSH. CONCLUSION: Apoptosis is a principle modality of cell death of small intestinal Peyer's patches lymphocytes in severely scalded mice, and it might contribute to immunity barrier failure of intestinal wall after severe thermal injury.