高迁徙率族蛋白1在急性胰腺炎大鼠中的表达及其意义

Expression and significance of high mobility group box 1 in rats with acute pancreatitis

目的探讨高迁徙率族蛋白1（HMGB1）在急性胰腺炎（AP）大鼠全身炎症反应中的作用及其机制。方法136只SD大鼠随机分为正常对照组（A组，n=8）、模型组（B组，n=64）、丙酮酸乙酯（EP）治疗组（C组，n=64）。B、C两组均分别采用2％与5％牛磺胆酸钠（2ml／kg）逆行注入胰胆管复制大鼠轻症急性胰腺炎（MAP）与重症急性胰腺炎（SAP）模型，C组大鼠在制模后2h经鼠尾静脉注射EP溶液（28mmol／L，40mr／kg），每6h1次，B组于同一时点注射等量的乳酸林格氏平衡液。A组大鼠直接取材，B、c两组分6、12、24、48h4个时点取材；逆转录一聚合酶链反应（1it-PCR）测定单个核细胞、胰腺组织HMGB1 mRNA表达，Westernblot法分析HMGB1蛋白表达；观察其病理形态变化，进行评分，并作HMGB1 mRNA、胰腺病理组织学评分的相关分析。结果A组胰腺组织HMGB1 mRNA表达量、胰腺病理评分分别为1．01±0．18、0．70±0．23，B组SAP模型胰腺组织HMGB1mRNA表达量分别为1．18±0．31、18．23±1．36、201．14±12．01、190．66±9．77，胰腺组织病理学评分分别为9．01±1．94、9．97±1．81、11．45±1．43、13．17±1．37；C组EP＋SAP模型胰腺组织HMGB1mRNA表达量分别为1．11±0．27、12．60±1．20、45．44±4．45、41．41±4．11，胰腺组织病理学评分分别为8．97±1．87、9．92±1．88、9．34±1．63、10．26±1．22；A、B两组胰腺组织HMGB1mRNA与胰腺病理组织学评分的相关系数r=0．847（P〈0．01）。结论复制AP模型后，HMGB1表达量12h开始上调，24h达峰值，48h仍处于高水平；HMGB1与AP严重程度高度正相关，作为晚期炎性因子在AP全身炎症反应中发挥重要作用，EP可通过抑制HMGB1表达，减轻大鼠胰腺损伤，对AP起治疗作用。

Objective To research the role of high mobility group box 1 （ HMGB1 ） in systemic inflammatory response in rats with acute pancreatitis （AP）. Methods The 136 Spragye-Dawley rats were randomly divided into three groups ： group A （ n = 8 ）, group B （n = 64） and group C （ n = 64）. AP models were induced by retrograde injection of sodium taucrocholate into the biliopancreatic duct： with 2% sodium taucrocholate to induce mild AP, and 5% to induce severe AP in group B and group C respectively. Group C received ethyl pyruvate （EP） solution （28 mmol/L, 40 mg/kg.6 h） by tail vein beginning at 2nd h after induction of AP, while group B received the same amount of ringer lactate solution balance as a placebo. The samples of the blood and pancreas were collected directly in group A, and after 6, 12, 24 and 48 h, the blood and pancreas were collected in groups B and C. Reverse transcription-polymerase chain reaction （RT-PCR） Western blotting were ued to detect mRNA and protein expression of HMGB1 respectively. A point scoring system histologic features were respectively used to evaluate the severity of pancreatitis, and correlation between HMGB1 mRNA expression and pancreatic histopathological score was analyzed. Results The expression levels of HMGB1 mRNA and the pancreas pathological scores in group A were 1.01 ±0. 18 and 0.70 ±0. 23 separately. The HMGB1 mRNA expression in the pancreatic tissue of group B at 6th, 12th, 24th and 48th h was separately 1.18 ±0. 31, 18.23 ± 1.36, 201.14 ± 12. 01 and 190. 66 ±9. 77, with histopathologieal scores of the pancreas being 9. 01 ± 1.94, 9. 97 ± 1.81, 11.45 ±1.43 and 13.17 ± 1.37. The HMGB1 mRNA expression in the pancreatic tissue of group C at at 6th, 12th, 24th and 48th h was separately 1.11±0. 27, 12. 60 ± 1.20, 45.44±4. 45, and 41.41± 4. 11, and histopathological scores of the pancreas were 8.97 ± 1.87, 9. 92 ±1.88, 9. 34 ± 1.63 and 10. 26 ±1.22 separately. The correlation coefficient of HMGB1 mRNA in pancreatic tissues and pancreatic histopathological scores in groups A and B was r = 0. 847 （P 〈 0. 01 ）. Conclusion The expression of HMGB1 was increased at 12th h, reached the peak at 24th h and stayed at a high level at 48th h. The increased HMGB1 was positively correlated wtih the severity of AP, suggesting its importanthy role in the systemic inflammatory response of AP. Treatment with EP has a therapeutic effect on AP by inhibitting HMGB1 expression, and reducing pancreatic injury.