重症急性胰腺炎大鼠p38丝裂原活化蛋白激酶的表达与肺毛细血管内皮屏障损伤

目的研究p38丝裂原活化蛋白激酶（p38 mitogen-activated protein kinase,p38MAPK）在重症急性胰腺炎（severe acute pancreatitis,SAP）大鼠肺组织中的表达情况,并初步探讨p38MAPK与SAP肺毛细血管内皮屏障损伤的关系。方法将40只健康雄性SD大鼠随机（随机数字表法）分为假手术（SO）组和SAP组,SAP组又再分为3、6、12及24 h 4个时间点组,共5组,每组8只。采用胰胆管逆行注射5%牛磺胆酸钠的方法建立SAP大鼠模型。采用HE染色方法观察大鼠肺和胰腺组织的病理学改变;采用ELISA法检测血清肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）水平;采用免疫组化染色方法检测肺组织中磷酸化p38（p-p38）蛋白和水通道蛋白1（AQP1）的表达水平;采用实时定量荧光PCR法（real-time PCR）检测肺组织中AQP1 mRNA的表达水平。结果 SAP各时间点组大鼠肺组织充血水肿,炎症细胞浸润;胰腺组织可见大片坏死,部分腺叶结构模糊甚至消失;血清TNF-α和IL-1β水平均较SO组高（P〈0.05）。SO组大鼠肺组织中p-p38蛋白仅有微量表达,而在SAP3 h组,p-p38蛋白的表达就明显上调,在6 h时达高峰,24 h时仍高于SO组（P〈0.05）。SAP各时间点组大鼠肺组织中AQP1 mRNA及其蛋白的表达水平均较SO组下降（P〈0.05）,并随着时间的推移而逐渐下降;SAP组大鼠AQP1 mRNA的表达与TNF-α、IL-1β及p-p38蛋白之间均存在负相关关系（r=-0.87,P〈0.05;r=-0.88,P〈0.05;r=-0.78,P〈0.05）。结论肺组织中AQP1蛋白表达的下调是SAP肺毛细血管内皮屏障损伤的重要原因之一,其可能与p38MAPK的激活及炎症因子的过度释放有关。

Expression of p38 Mitogen-Activated Protein Kinase and Pulmonary Capillary Barrier Injury in Rats with Severe Acute Pancreatitis

Objective To investgate the expression of p38 mitogen-activated protein kinase（p38MAPK） in lung tissue of rats with severe acute pancreatitis（SAP）,and to explore the relationship between p38MAPK and pulmonary capillary barrier injury.Methods Forty male and healthy Sprague-Dawley（SD） rats were randomly（random number method） divided into sham operation（SO） group and SAP group,then rats of SAP group were sub-divided into 3,6,12,and 24 h group,each group enrolled 8 rats,respectively.SAP model rats were established by injecting 5% sodium taurocholate solution retrograde into the biliopancreatic duct.ELISA method was used to test the serum tumor necrosis factor-α（TNF-α） and interleukin-1β（IL-1β）,and pathological changes in lung and pancreas tissues were observed by HE staining.Immunohischemistry method was used to detect phosphorylated p38（p-p38） protein and aquaporin 1（AQP1） protein of lung tissues.The expression level of AQP1 mRNA was measured by quantitative real-time PCR.Results Hyperemia,edema,and inflammatory cell infiltration were observed in lung tissues,abundance of necrosis,part gland structure fuzzy or even disappear were observed in pancreas tissues of all 4 time point groups.Compared with SO group,levels of serum TNF-α and IL-1β were significantly higher in 4 time point groups（P0.05）.Lower expression level of p-p38 protein was detected in lung tissues of SO group,while in the early stage of SAP（SAP 3 h group）,the expression level of p-p38 protein significantly increased,which peaked in 6 h group and was still higher than SO group in 24 h group（P0.05）.Compared with SO group,the expression levels of AQP1 mRNA and protein were significantly lower in all 4 time point groups（P0.05）,which had negative correlation with the levels of serum TNF-α, IL-1β,and the expression level of p-p38 protein（r=-0.87,P0.05;r=-0.88,P0.05;r=-0.78,P0.05）.Conclusion The decrease of AQP1 protein in lung tissue is one of the vital causes for pulmonary capillary barrier injury in SAP,which probably works by the activation of p38MAPK and the excessive release of inflammatory cytokines.