Caspase抑制剂Z-VAD-fmk对重症胰腺炎肠道屏障的保护作用

目的 建立重症胰腺炎（SAP）SD大鼠模型,观察其肠道超微结构及其通透性的变化,探讨半胱氨酸蛋白酶（Caspase）抑制剂N-苯甲基化碳酰-缬氨酸-丙氨酸-天冬氨酸-氟化丙酮（z-VAD-fmk）对肠道屏障功能（IBF）的影响.方法 将72只SD大鼠随机分成3组：假手术组（sham组,n=24）,重症胰腺炎组（SAP组,n=24）.Z-VAD-fmk干预组（Z-VAD-fmk组,n=24）,Z-VAD-fmk组于制模前腹腔注射Z-VAD-fmk溶液.测定各组SD大鼠的血清肠脂肪酸结合蛋白（IFABP）、回肠组织Caspase-3水平,观察其回肠病理变化、组织超微结构改变及上皮细胞凋亡情况,并进行组问比较.结果 SAP组SD大鼠可见回肠病理改变及超微结构异常明显,上皮凋亡阳性细胞较多;Z-VAD-fmk组的病理改变、组织超微结构异常均较SAP组减轻,凋亡阳性细胞较SAP组减少,且各时点血清IFABP水平及组织Capcase-3水平较SAP组均显著下降（均P〈0.05）,sham组上述改变均不明显.结论 SAP可导致SD大鼠肠道超微结构显著异常、IBF受损,肠上皮细胞有不同程度的坏死和凋亡,SAP发病早期肠上皮细胞凋亡和增生之间失去平衡是IBF障碍的病理机制之一,予z-VAD-fmk干预可以改善SAP发病后的肠道病理改变和超微结构异常,其作用可能是通过抑制肠上皮细胞凋亡来实现的.

Protective effects of caspase inhibitor z-VAD-fmk on intestinal barrier in rats with experimental severe acute pancreatitis

Objective To investigate the protective effect of caspase inhibitor z-VAD -fmk on the intestinal barrier in rats with severe acute pancreatitis （SAP）. Methods Seventy-two rats were randomly divided into 3 groups： sham operation group; SAP group; and SAP with z-VAD -fmk group. The rats in z-VAD -fmk group received intraperitoneal injection of z-VAD -fmk at 30 mins before operation. Apopfosis of intestinal epithelium was examined by the TUNEL method. Segments of ileum were stained and examined under light microscopy and transmission electron microscopy. Serum intestinal fatty acid binging protein （I-FABP） levels were determined using the commercial kits, the level of Ileal caspase-3 was analyzed by chromatometry. Results In comparison with sham group the intestinal specimens of SAP group showed marked morphologic alterations; cell apoptosis was markedly increased, serum I-FABP levels began to increase at 4 h and reached the peak level at 24 h. Z-VAD-fmk group showed less microscopic injury and apoptosis in the ileum tissue and a decreased intestinal permeability. Conclusion Cas- pase-3 inhibitor Z-VAD-fmk shows a protective effect on the intestinal barrier and contributes to prevent bacterial translocation in severe acute pancreatitis of rats.