Coopersmith Craig M, Stromberg Paul E, Davis Christopher G, Dunne W Michael, Amiot Daniel M, Karl Irene E, Hotchkiss Richard S, Buchman Timothy G
Department of Surgery, Washiongton University School of Medicine, St. Louis, MO, USA.
Crit Care Med. 2003 Jun;31(6):1630-7. doi: 10.1097/01.CCM.0000055385.29232.11.
To evaluate whether the up-regulation in sepsis-induced gut epithelial apoptosis is balanced by an increase in intestinal proliferation and to assess mechanisms affecting the gut's regenerative response to overwhelming infection.
Prospective, randomized, controlled study.
Animal laboratory in a university medical center.
Mice were subjected to intratracheal injection of Pseudomonas aeruginosa and killed between 1.5 and 24 hrs after induction of pneumonia-induced sepsis to assess for gut epithelial proliferation and cell division and for apoptosis. Animals were compared with sham-operation controls, septic transgenic mice that overexpress Bcl-2 throughout their small intestinal epithelium, and septic p53-/- mice.
Proliferation and cell division were assessed by measuring S-phase and M-phase cells in intestinal crypts. The number of S-phase cells showed a progressive decline at all time points measured, with a 5-fold decrease in proliferation between control animals and septic mice 24 hrs after intratracheal injection of pathogenic bacteria (p <.0001). In contrast, cells in M-phase remained constant for the first 12 hrs after the onset of sepsis, but increased nearly 50% at 24 hrs after instillation of P. aeruginosa (p <.005). Both the decrease in S-phase cells and the increase in M-phase cells were partially suppressible in Bcl-2 overexpressors, but cellular proliferation and division were similar between septic p53-/- and p53+/+ mice. Crypt apoptosis was increased at all time points, with maximal death occurring between 12 and 24 hrs.
Sepsis from P. aeruginosa pneumonia induces a p53-independent decrease in gut epithelial proliferation. Despite an increase in sepsis-induced intestinal apoptosis, there is no compensatory increase in intestinal epithelial proliferation, and there is evidence of a cell cycle block with an accumulation of cells in M-phase. Decreasing gut apoptosis by overexpression of Bcl-2 is associated with a partial reversal of the effect of sepsis on the cell cycle.
评估脓毒症诱导的肠道上皮细胞凋亡上调是否被肠道增殖增加所平衡，并评估影响肠道对严重感染的再生反应的机制。
前瞻性、随机、对照研究。
大学医学中心的动物实验室。
对小鼠进行气管内注射铜绿假单胞菌，并在诱导肺炎性脓毒症后1.5至24小时之间处死，以评估肠道上皮细胞增殖、细胞分裂及凋亡情况。将动物与假手术对照组、在整个小肠上皮中过表达Bcl-2的脓毒症转基因小鼠以及脓毒症p53基因敲除小鼠进行比较。
通过测量肠隐窝中的S期和M期细胞来评估增殖和细胞分裂。在所有测量时间点，S期细胞数量均呈逐渐下降趋势，在气管内注射病原菌后24小时，对照动物与脓毒症小鼠之间的增殖下降了5倍（p<.0001）。相比之下，脓毒症发作后的前12小时，M期细胞数量保持恒定，但在滴注铜绿假单胞菌后24小时增加了近50%（p<.005）。Bcl-2过表达小鼠中S期细胞的减少和M期细胞的增加均部分受到抑制，但脓毒症p53基因敲除小鼠与p53基因野生型小鼠之间的细胞增殖和分裂情况相似。在所有时间点，隐窝凋亡均增加，最大死亡发生在12至24小时之间。
铜绿假单胞菌肺炎引起的脓毒症导致肠道上皮细胞增殖出现不依赖p53的下降。尽管脓毒症诱导的肠道凋亡增加，但肠道上皮细胞增殖并未出现代偿性增加，且有证据表明细胞周期阻滞，M期细胞积聚。通过过表达Bcl-2减少肠道凋亡与脓毒症对细胞周期影响的部分逆转相关。
