磷脂酰肌醇3-激酶γ在实验小鼠急性胰腺炎腺泡细胞坏死中的作用

The role of phosphatidylinositide 3-kinase gamma （PI3Kγ） in mediating acinar cell necrosis in rat models with acute pancreatitis

目的研究磷脂酰肌醇3-激酶7（P13KT）在实验性急性胰腺炎腺泡细胞坏死中的作用，并探讨其作用机制。方法12只雄性野生型C57BL／6小鼠和12只雄性P13K7基因敲除小鼠随机分为对照组和胰腺炎组，腹腔内分别注射生理盐水和蛙皮素（50μg／kg）诱导急性胰腺炎模型。观察两种动物模型胰腺组织病理变化，同时检测血清胰蛋白酶活性、组织蛋白酶B和L活性的变化，Westernblotting检测组织蛋白酶B和L蛋白的表达。结果组织学显示，P13K7基因敲除小鼠胰腺炎腺泡细胞坏死数量[（2．25±0．54）／HP比（5．14±0．85）／HP]和空泡数量[（1．24±0．21）／HP比（2．36±0．34）／HP]明显少于野生型小鼠（P〈0．05），组织蛋白酶BE（1232士21）pmolAMC／min／mg比（1891土35）pmolAMC／min／mg]和胰蛋白酶活性[（0．358±0．098）pmol／mg比（0．827土0．126）pmol／mg-]低于野生型小鼠（P〈0．05），而组织蛋白酶L活性相反[（415±11）pmolAMC／min／mg比（346±6）pmolAMC／min／mg]（P〈O．01）。结论P13K7在急性胰腺炎时可能具有促进细胞坏死的作用，其可能机制是改变了组织蛋白酶B和L之间的平衡和促进了胰蛋白酶原的活化。

Objective To study the role and mechanism of phosphatidylinositide 3-kinase gam- ma （PI3Kγ） in mediating acinar cell necrosis in rat models with acute pancreatitis. Methods Twelve male C57BL/6 wild-type and twelve male PI3Kγ knockout mice were randomly divided into saline group and pancreatitis group. The pancreatitis group received an intraperitoneal injection of cerulean （50 μg/kg） to induce acute panreatitis. Pathologic changes in the two groups were observed by measuring the trypsin, cathepsin B, and cathepsin L activity. The protein expressions of cathepsin B and cathepsin L were detected by the Western blot assay. Results Compared with the wild-type mice, the PI3K7 knockout mice had fewer acinar cell necrosis [-（2.25±0.54）/HP vs （5. 145=0.85）/HP] and vacuoles [-（1.24±0. 21）/HP vs （2.36±0.34）/HP]according to histology. The cathepsin B activity [-（1232±21）pmolAMC/min/mg vs （1891± 35） pmolAMC/min/mg] and trypsin activity [（0. 358± 0. 098）pmol/mg vs （0. 827 ＋ 0. 126）pmol/mg] were significantly decreased in the pancreatitis group （P〈0.05） compared to the saline group. However, the cathepsin L activity [-（415± 11）pmolAMC/ min/mg vs （346± 6）pmolAMC/min/mg] was significantly higher in PI3K）＇ knockout mice than in wild-type mice（P〈0.01）. Conclusions PI3Kγ may promote cell necrosis in acute pancreatitis by possibly changing the balance between cathepsin B and cathepsin L levels to promote the activation of trypsinogen.