中度低温对急性出血坏死性胰腺炎大鼠胰腺损伤的保护作用

Effects of moderate hypothermia on pancreatic injury and survival in rats with acute hemorrhagic necrotizing pancreatitis

目的 观察中度低温对急性出血坏死性胰腺炎(AHNP)大鼠胰腺损伤和死亡率的影响。方法将112只大鼠随机分为假手术组(n=24)、AHNP常温组(n=44)和AHNP低温组(n=44)。以牛磺胆酸钠逆行注射制备大鼠AHNP模型,低温组诱导AHNP后通过体表降温将体温控制在32.0-33.0℃。各组中24只大鼠分别在AHNP诱导后第2和5 h取标本,观察血清淀粉酶、脂肪酶以及胰腺血管通透性变化、病理形态学改变和胰腺组织湿重／干重比值。AHNP常温组和低温组中余20只大鼠将体温控制在预定范围12 h,观察大鼠72 h的生存率。结果 与AHNP常温组比较,低温组AHNP后2、5 h血清淀粉酶和脂肪酶水平、血管渗透指数及AHNP后5 h胰腺组织水肿程度均明显降低(P均<0.05)。AHNP常温组平均生存时间是7.5 h(3.0-18.0 h),而低温组则延长至25.5 h(13.0-72.0 h)。低温组大鼠生存率显著高于常温组(P=0.000 1)。结论 急性胰腺炎应用中度低温可减轻胰腺损伤,延长大鼠生存时间,提示低温有可能作为一项有益的辅助措施用于急性胰腺炎的治疗中。

Objective To investigate the effect of moderate hypothermia on pancreatic injury and survival of rats with acute hemorrhagic necrotizing pancreatitis (AHNP). Methods A set of 112 rats were randomly divided into three equal groups: ①sham-operated rats(n=24) which were kept at 37.0-37. 5℃ after laparotomy;②AHNP rats(n= 44) treated with normothermia (37.0-37.5℃;③HNP rats(n=44) treated with moderate hypothermia (32.0-33.0℃). AHNP was induced by the infusion of 5% sodium taurocholate. Hypothermia was induced immediately after induction of pancreatitis by surface cooling until their rectal temperature reached 32.0- 33.0℃. Samples were obtained at 2 or 5 hours after pancreatitis induction in 24 rats of each group. Changes in serum amylase, lipase, wet/dry weight ratio and vascular permeability index, as well as pathology were observed. Another 40 rats of normothermic or hypothermic groups with AHNP were kept at scheduled temperature for 12 hours after pancreatitis induction. Survival was monitored for 72 hours. Results Serum amylase and lipase levels, vascular permeability index were significantly reduced at 2 or 5 hours, and pancreatic edema significantly reduced at 5 hours after pancreatitis induction in hypothermic group compared with normothermic group (all P<0. 05). Mean survival time, which was 7.5 hours (3.0-18.0 hours) in normothermic group, was prolonged with hypothermia to 25. 5 hours (13.0-72.0 hours) . The survival of hypothermic animals was higher than normothermic ones after pancreatitis induction (P=0.0001). Conclusion Moderate hypothermia applied after pancreatitis induction can provide protection against pancreatic injury, and increase survival in rats with AHNP. While the mechanism underlying this protection remains to be clarified, the findings of present study have implications for the possibility that hypothermia may be helpful as an adjunctive clinical therapy in acute pancreatitis.