Frossard Jean-Louis, Rubbia-Brandt Laura, Wallig Matthew A, Benathan Messod, Ott Thomas, Morel Philippe, Hadengue Antoine, Suter Susanne, Willecke Klaus, Chanson Marc
Divisions of Gastroenterology, University Hospitals, Geneva, Switzerland.
Gastroenterology. 2003 Feb;124(2):481-93. doi: 10.1053/gast.2003.50052.
BACKGROUND & AIMS: The early events leading to acinar cell injury during acute pancreatitis are poorly characterized. Signaling through gap junction channels contributes to the homeostasis of the exocrine pancreas by coordinating acinar cell activity within an acinus. To explore the role of gap junctional communication in acinar cell response to injury, we analyzed the course of acute pancreatitis induced by injection of cerulein in mice deficient for Cx32, the major gap junction protein expressed in the exocrine pancreas.
The severity of pancreatitis was evidenced by measuring serum amylase activity, pancreatic edema, acinar cell necrosis, pancreatic tumor necrosis factor alpha concentration, and myeloperoxidase activity. Acinar cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL), caspase-3 activity, and Bax/Bcl-2 expression. Expression and function of connexin were evaluated by immunofluorescence and dye coupling.
Cx32-deficient mice exhibited a deleterious course of acute pancreatitis with increased necrosis, edema, and inflammation of the exocrine pancreas. In addition, the exocrine pancreas of Cx32-deficient mice showed a decreased number of TUNEL-positive acinar cells and decreased caspase-3 activity but no change in Bax or Bcl-2 pancreatic expression. Interestingly, chemicals known to induce apoptosis in vivo had no effect on Cx32-deficient pancreatic acinar cells.
Deficiency of a pancreatic connexin converts a mild reversible form of acute pancreatitis into a severe disease and decreases the sensitivity of acinar cells to apoptotic stimuli. The results show that acinar cell-to-cell communication plays a key role in the modulation of severity of acute pancreatitis.
急性胰腺炎期间导致腺泡细胞损伤的早期事件目前尚不清楚。通过间隙连接通道进行的信号传导通过协调腺泡内的腺泡细胞活性，有助于外分泌胰腺的内环境稳定。为了探究间隙连接通讯在腺泡细胞对损伤反应中的作用，我们分析了在缺乏Cx32（外分泌胰腺中表达的主要间隙连接蛋白）的小鼠中注射蛙皮素诱导的急性胰腺炎的病程。
通过测量血清淀粉酶活性、胰腺水肿、腺泡细胞坏死、胰腺肿瘤坏死因子α浓度和髓过氧化物酶活性来证明胰腺炎的严重程度。通过末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸缺口末端标记（TUNEL）、半胱天冬酶-3活性以及Bax/Bcl-2表达来检测腺泡细胞凋亡。通过免疫荧光和染料偶联评估连接蛋白的表达和功能。
缺乏Cx32的小鼠表现出急性胰腺炎的有害病程，外分泌胰腺的坏死、水肿和炎症增加。此外，缺乏Cx32的小鼠的外分泌胰腺显示TUNEL阳性腺泡细胞数量减少，半胱天冬酶-3活性降低，但胰腺中Bax或Bcl-2的表达没有变化。有趣的是，已知在体内诱导凋亡的化学物质对缺乏Cx32的胰腺腺泡细胞没有影响。
胰腺连接蛋白的缺乏将轻度可逆形式的急性胰腺炎转变为严重疾病，并降低腺泡细胞对凋亡刺激的敏感性。结果表明，腺泡细胞间通讯在调节急性胰腺炎的严重程度中起关键作用。
