脓毒症大鼠肠系膜淋巴结与机体免疫功能相关性研究

目的 探讨脓毒症大鼠肠系膜淋巴结(MLN)与机体促炎/抗炎免疫状态变化及其相关性.方法 雄性Wistar大鼠96只,按随机数字表法分为假手术组和模型组.采用盲肠结扎穿孔术(CLP)制备大鼠脓毒症模型,于术后0、6、12、24、48和72 h各取8只大鼠腹主动脉血和MLN组织,采用流式细胞仪测定全血与MLN中辅助性T细胞1/2(Th1/Th2)比值及调节性T细胞(Treg细胞)占CD4+T淋巴细胞的比例.结果 模型组腹主动脉血中Th1/Th2比值于术后6 h显著升高,12 h达高峰,随后持续降低;与假手术组比较,模型组术后6、12、24 h Th1/Th2比值显著升高(0.82±0.15比0.60±0.22,1.23±0.44比0.76±0.31,0.85±0.25比0.66±0.32),72 h显著降低(0.41±0.16比0.59±0.13,P＜0.05或P＜0.01).模型组MLN中Th1/Th2比值于术后6 h达峰值,然后显著下降;与假手术组比较,模型组术后6 h Th1/Th2比值显著升高(1.01±0.16比0.52±0.13),12、24、48、72 h显著下降(0.34±0.11比0.53±0.09,0.23±0.08比0.51±0.09,0.17±0.07比0.47±0.15,0.16±0.06比0.53±0.11,P＜0.05或P＜0.01).模型组MLN中Treg细胞比例于术后12、24、48、72 h显著高于假手术组(9.62±0.69比7.65±0.67,9.84±0.74比8.08±1.06,10.95±2.09比7.83±1.15,10.81±1.34比8.35±1.12,P＜0.05或P＜0.01).MLN中Th1/Th2比值与Treg细胞比例呈线性负相关(r=-0.882,P＜0.05).结论 严重腹腔感染导致肠源性内毒素通过MLN系统移位,MLN免疫功能障碍加速内毒素人血,进而影响全身的免疫功能,产生Th1向Th2的漂移.MLN免疫功能降低可能与内毒素介导MLN中Treg细胞比例升高有关.

Abstract：

Objective To investigate the changes in T helper cells (Th1 and Th2) of mesenteric lymph node (MLN) and blood Th1 and Th2 cells in septic rats. Methods Ninety-six male Wistar rats were randomly divided into two groups according to random number table method: sham operation group and model group. Intra-abdominal infection with sepsis was induced by cecal ligation and puncture (CLP). Eight rats in each group were sacrificed after collection of blood samples and MLN samples at 0, 6, 12, 24, 48 and 72 hours after CLP. The ratio of Th1/Th2 and the percentage of regulatory T cell (Treg) in CD4+ T cells in blood and MLN were respectively determined by flow cytometry. Results In model group, the ratio of Th1/Th2 in abdominal aorta blood increased significantly at 6 hours and reached summit at 12 hours, then it decreased persistently, and when compared with sham group, the ratio of Th1/Th2 was significantly higher at 6, 12, 24 hours (0.82±0.15 vs. 0. 60±0. 22, 1. 23±0. 44 vs. 0. 76±0. 31, 0. 85±0. 25 vs. 0. 66±0. 32)and lower at 72 hours (0. 41±0.16 vs. 0. 59±0. 13, P＜0. 05 or P＜0. 01). The ratio of Th1/Th2 in MLN of model group reached summit at 6 hours, then decreased significantly, and when compared with sham group, the ratio of Th1/Th2 was significantly higher at 6 hours (1. 01±0.16 vs. 0. 52±0.13) and lower at 12, 24, 48 and 72 hours (0. 34±0.11 vs. 0. 53±0. 09, 0. 23±0. 08 vs. 0. 51±0. 09, 0.17±0. 07 vs. 0. 47±0.15, 0.16±0. 06 vs. 0. 53±0.11, P＜0. 05 or P＜0. 01). Compared with sham group, the percentage of Treg in MLN of model group was increased at 12, 24, 48 and 72 hours after CLP (9. 62±0. 69 vs. 7. 65±0.67, 9. 84±0. 74 vs. 8.08±1. 06, 10. 95±2. 09 vs. 7. 83±1.15, 10. 81±1. 34 vs. 8. 35±1.12, P＜0. 05 or P＜0. 01). There was a negative correlation between the ratio of Th1/Th2 and the percentage of Treg in MLN (r=-0. 882, P＜0. 05). Conclusion Cellular immune function of MLN is suppressed during severe intra-abdominal infection, which induces translocation of gut-derived endotoxin to mesenteric lymphatics,resulting in corporal immuno-suppression, with manifestation of Th1/Th2 cell shift. Immuno-suppression of MLN is related to a higher percentage of Treg due to the effect of endotoxin.

Relation of mesenteric lymph node and innate immune function in septic rats

Objective To investigate the changes in T helper cells (Th1 and Th2) of mesenteric lymph node (MLN) and blood Th1 and Th2 cells in septic rats. Methods Ninety-six male Wistar rats were randomly divided into two groups according to random number table method: sham operation group and model group. Intra-abdominal infection with sepsis was induced by cecal ligation and puncture (CLP). Eight rats in each group were sacrificed after collection of blood samples and MLN samples at 0, 6, 12, 24, 48 and 72 hours after CLP. The ratio of Th1/Th2 and the percentage of regulatory T cell (Treg) in CD4+ T cells in blood and MLN were respectively determined by flow cytometry. Results In model group, the ratio of Th1/Th2 in abdominal aorta blood increased significantly at 6 hours and reached summit at 12 hours, then it decreased persistently, and when compared with sham group, the ratio of Th1/Th2 was significantly higher at 6, 12, 24 hours (0.82±0.15 vs. 0. 60±0. 22, 1. 23±0. 44 vs. 0. 76±0. 31, 0. 85±0. 25 vs. 0. 66±0. 32)and lower at 72 hours (0. 41±0.16 vs. 0. 59±0. 13, P＜0. 05 or P＜0. 01). The ratio of Th1/Th2 in MLN of model group reached summit at 6 hours, then decreased significantly, and when compared with sham group, the ratio of Th1/Th2 was significantly higher at 6 hours (1. 01±0.16 vs. 0. 52±0.13) and lower at 12, 24, 48 and 72 hours (0. 34±0.11 vs. 0. 53±0. 09, 0. 23±0. 08 vs. 0. 51±0. 09, 0.17±0. 07 vs. 0. 47±0.15, 0.16±0. 06 vs. 0. 53±0.11, P＜0. 05 or P＜0. 01). Compared with sham group, the percentage of Treg in MLN of model group was increased at 12, 24, 48 and 72 hours after CLP (9. 62±0. 69 vs. 7. 65±0.67, 9. 84±0. 74 vs. 8.08±1. 06, 10. 95±2. 09 vs. 7. 83±1.15, 10. 81±1. 34 vs. 8. 35±1.12, P＜0. 05 or P＜0. 01). There was a negative correlation between the ratio of Th1/Th2 and the percentage of Treg in MLN (r=-0. 882, P＜0. 05). Conclusion Cellular immune function of MLN is suppressed during severe intra-abdominal infection, which induces translocation of gut-derived endotoxin to mesenteric lymphatics,resulting in corporal immuno-suppression, with manifestation of Th1/Th2 cell shift. Immuno-suppression of MLN is related to a higher percentage of Treg due to the effect of endotoxin.