Disruption of gut barrier function and cytokine responses after severe surgical stress-mechanism and treatment

研究了生长激素（GH）和胰岛素样生长因子I （IGF-I）对烧伤肠源性脓毒症的影响。BALB/c小鼠（n=50）皮下注射4.8mg/kg/天GH、24mg/kg/天IGF-I或安慰剂，每天2次，连续4天。然后用10^<10>E灌胃。大肠杆菌受到20%的全病火焰烧伤。所有小鼠在烧伤前5天接受同种异体输血，引起轻度免疫抑制。30只小鼠观察存活，20只小鼠在烧伤后20小时处死。GH和igf - 1的使用减少了烧伤后20小时向MLN和其他器官转移的发生率，并显著提高了生存率。我们得出结论，生长激素和igf - 1可能在危重疾病中有用。先前的研究表明，细菌易位与烧伤后的死亡率高度相关。为了进一步阐明细菌易位相关器官功能障碍和继发性死亡的机制，我们研究了细菌易位程度与肝脏中性粒细胞积累的关系。输血Balb/c小鼠分别口服200mg/kg/d依异prost （PGEl类似物）或生理盐水3 d，然后灌胃10^<10 14> c大肠杆菌，造成20%的全病火焰烧伤。根据我们之前的调查，这些小鼠的死亡率约为80%，而依异前列素将死亡率提高到30%。烧伤后24小时处死动物，取肠系膜淋巴结（MLN）、肝脏和脾脏。通过放射性核素计数（dpm）和活菌落计数在MLN和肝脏中测定细菌易位。通过测量肝脏中髓过氧化物酶（MPO）来评估白细胞积累。与之前的研究一致，异丙素显著减少了易位。对照组肝脏MPO明显高于依异前列素组。MPO与细菌易位程度有显著相关（p<0.05）。由此可见，细菌易位增加了肝脏中性粒细胞的积累，这可能是烧伤后器官损伤的原因。实验三采用与实验二相同的模型，分离脾巨噬细胞，分别添加和不添加10mcg/ml LPS培养24小时。检测细胞培养上清液中TNF、IL-1、IL-6、PGE2的含量。LPS刺激巨噬细胞产生IL-1、IL-6和PGE2在异prost处理的动物中显著增加。这很可能是由于先前在体内缺乏对巨噬细胞的最大刺激，在体外进一步用LPS刺激巨噬细胞后，巨噬细胞产生了更多的细胞因子。少

Experimenr IEffects of growth hormone (GH) and insulin-like growth factor I (IGF-I) administration on burn induced gut derived sepsis was evaluated. BALB/c mice (n=50) were treated subcutaneously with 4.8mg/kg/day of GH,24mg/kg/day of IGF-I or placebo twice a day for 4 days. Then they were gavaged with 10^<10>E.coli and subjected to 20% full sickness flame burn. All mice received allogeneic blood transfusion 5 days before burn to induce mild immunosuppression. Thirty mice were observed for survival and twenty mice were sacrificed at 20 hours post burn. GH and IGF-I administration reduced the incidence of translocation to MLN and other organs 20 hours post burn and significantly improved survival. We conclude that GH and IGF-I may be useful during critical illness.Experiment IIThe previous investigation revealed that bacterial translocation is highly associated with mortality after burn injury. To further clarify the mechanism of bacterial translocation related organ dysfunction and sub … More sequent death, we investigated the relation between the degree bacterial translocation and neutrophil accumulation in the liver.Blood transfused Balb/c mice were treated with oral 200mg/kg/day enisoprost (PGEl analog) or saline for three days and then they were gavaged with 10^<10 14>C E.coli and 20% full sickness flame burn was inflicted. According to our previous investigation, these mice have a mortality rate of approximately 80% and enisoprost improved the mortality to up to 30%. Animals were sacrificed 24 hour post burn and mesenteric lymph node (MLN), Liver, and spleen were harvested. Bacterial translocation were determined by both radionuclide count (dpm) and viable colony count in the MLN and Liver. Leukocyte accumulation was evaluated by the measurement of myeloperoxidase (MPO) in the liver. Consistent to previous work, enisoprost significantly reduced the translocation. MPO in the liver was significantly greater in the control group compared to enisoprost group. There was a significant correlation between MPO and the degree of bacterial translocation (p<0.05). It can concluded that bacterial translocation enhanced neutrophil accumulation in the liver which may be the cause of organ injury after burn injury.Experiment IIIUsing the same model as experiment II,splenic macrophages were separated and cultured for 24 hours with and without 10mcg/ml of LPS.TNF,IL-1 IL-6 and PGE2 in the cell culture supernatants were measured. LPS stimulated macrophage production of IL-1, IL-6 and PGE2 were significantly greater in enisoprost treated animals. It is likely that prior lack of in vivo maximal stimulation of macrophages in the enisoprost treated animals can produce greater amounts of cytokines when further stimulated with LPS in vitro. Less