脂氧素A4类似物对急性胰腺炎大鼠的保护作用及其机制

Protective effects and possible mechanism of lipoxin A4 analogue in rats with acute pancreatitis

目的探讨脂氧素A4（LXA4）类似物（LXA4-ME）对急性胰腺炎（AP）大鼠的保护作用及其作用机制。方法将120只SD大鼠按数字表法随机分为假手术组、急性胰腺炎组（AP组）及LXA4-ME治疗组（LXA4-ME组），各40只。逆胰胆管注射5％牛磺胆酸钠（1ml／kg）建立AP模型。LXA4-ME组在造模后经尾静脉注射含LXA4-ME（87．5μg／kg）的生理盐水1ml。假手术组及AP组造模后经尾静脉注射等量生理盐水。于12、24h观察大鼠腹水的性质、量及胰腺病理学变化。测定血浆淀粉酶（AMY）含量。检测各组胰腺髓过氧化物酶（MPO）活性及丙二醛含量。反转录（RT）-PCR法检测各组胰腺肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β、IL-10及细胞间黏附分子（ICAM）-1、E-选择素、核因子KBp65的mRNA表达水平。免疫组织化学法检测各组胰腺核因子KBp65蛋白的表达。结果LXA4-ME组大鼠12、24h腹水量[（6．88±1．23）、（6．53±0．91）m1]及胰腺病理学评分（8．7±1．3、7．8±1．1）均明显低于AP组[（12．32±1．94）、（14．15±1．68）ml，11．3±1．5、11．7±0．8，均P〈0．01]；12、24h胰腺MPO活性、丙二醛及AMY水平均显著低于AP组（均P〈0．01）；胰腺TNF-α、IL-1β、ICAM-1、E-选择素、核因子KBp65的mRNA表达水平也均显著低于AP组（均P〈0．01）。而IL-10mRNA表达水平均高于AP组（均P〈0．01）；12、24h胰腺核因子KBp65蛋白表达阳性率（24．8％±3．0％、31．6％±3．0％）显著低于AP组相应时间点（45．3％±3．4％、48．1％±4．6％，均P〈0．01）。结论LXA4-ME对AP大鼠具有一定的保护作用，其保护机制可能与减少核因子KB的激活有关。

Objective To explore the protective effects and possible mechanism of lipoxin A4- methyl ester （ LXA4-ME） in rats with acute pancreatitis （AP）. Methods A total of 120 male SD rats were randomly divided into 3 groups ： Sham operation （ n = 40 ）, AP （ n = 40 ） and LXA4-ME （ n = 40）. Sham operation group received normal saline after sham operation. AP was induced by a retrograde infusion of 5% sodium taurocholate into panereatobiliary duet. AP group received normal saline after modeling. In the LXA4-ME group, LXA4-ME was administered （87. 5 μg/kg） intraveneously after the onset of AP. The rats were sacrificed at 12 h and 24 h post-induction. Their serum levels of amylase were detected. The amount of ascites was calculated and histological changes of pancreas were observed. The activities of myeloperoxidase （MPO） and levels of malonaldehyde （MDA） in pancreas were determined. The mRNA levels of tumor necrosis factor （TNF）-α, interleukin （IL）-llS, IL-10, intercellular adhesion molecule （ICAM-1）, E- selectin and nuclear factor （NF）-KB 1365 in pancreas were measured by reverse transcription-polymerase chain reaction （RT-PCR） . The expression of NF-KB 1365 protein was also measured by immunohistochemistry. Results Compared with the AP group, the pathological scores of the LXA4-ME group improved （ 12 h： 8.7±1.3 vs 11.3 ± 1.5,24 h： 7.8 ± 1.1 vs 11.7 ＋0. 8） and the amount of ascites was lower（ 12h： （6.88±1.23） mlvs （12.32±1.94） ml,24 h： （6.53±0.91） mlvs （14.15±1.68） ml, all P 〈 0.01 ）. The serum levels of amylase in the LXAa-ME group were significantly lower than those in the AP group respectively at 12 h and 24 h post-operation（ all P 〈 0.01 ）. The activity of MPO and the level of MDA in pancreas in the LXA4-ME group were significantly lower than those in the AP group （ all P 〈 0. 01 ）. The pancreatic expressions of TNF-α mRNA, IL-lβ mRNA, ICAM-1 mRNA, E-selectin mRNA and NF-KB p65 mRNA at 12 h and 24 h decreased in the LXA4-ME group versus the AP group at the corresponding timepoints （all P 〈 0. 01 ）while the expression of IL-10 mRNA increased versus the AP group at the corresponding timepoints （ all P 〈 0. 01 ） . Compared with that in the AP group, the pancreatic expression of NF-KB p65 protein decreased in the LXA4-ME group （ 12 h： 24.8% ± 3.0% vs 45.3% ± 3.4%, 24h： 31.6% ±3.0% vs 48. 1% ±4.6%, both P 〈0.01）.Conclusion LXAn-ME exerts protective effects in AP rats. And its mechanism may be