紧密连接蛋白occludin在急性坏死性胰腺炎大鼠脑微血管内皮细胞的表达

Expression of tight junction protein occludin in the brain microvascular endothelial cells of rats with acute necrotizing pancreatitis

目的研究ANP大鼠脑微血管内皮细胞紧密连接蛋白occludin表达的变化及与胰腺病变程度的关系。方法80只大鼠按完全随机法分为假手术（SO）组和ANP3、6、12、24h组。以5％胆酸钠逆行性胰胆管注射诱导ANP大鼠动物模型，行胰腺组织病理学评价，应用免疫组织化学法、RT—PCR法及Western blotting法检测大鼠脑微血管内皮细胞间紧密连接蛋白occludin及其mRNA表达。结果occludin蛋白沿脑血管线性表达。ANP 3h组蛋白表达量从SO组的0．49±0．08下降到0．35±0．09；occludin mRNA表达从1．50±0．30减少到1．01±0．18（P〈0．05）。ANP 6h组达最低值，分别为0．26±0．07和0．93±0．19。ANP 12、24h组occludin蛋白和mRNA表达量又较ANP 6h组增加（P〈0．05），但仍低于SO组（P〈0．05）。occludin蛋白及mRNA表达与胰腺组织损害程度呈明显负相关（Pearson相关系数分别为-0．48和-0．536，P〈0．05）。结论在ANP进程中，脑微血管内皮细胞间紧密连接蛋白occludin及其mRNA均呈下调趋势，且与胰腺病变程度呈负相关。

Objective To explore the changes of expression of tight junction protein occludin in the brain microvascular endothelial cells of rats with acute necrotizing pancreatitis （ ANP）, and to study the relationship between the occludin expression and degree of pancreatic pathologic changes. Methods 80 rats were randomly divided into sham-operation （SO） group and ANP 3 h, 6 h, 12 h, and 24 h groups. Retrograde pancreatic duct injection of 5% choleate sodium in rats was used to establish ANP models. Panereatic pathologic changes was evaluated. Immunohistochemistry, Western blot and RT-PCR were used to determine the expressions of the tight junction protein occludin in the brain microvascular endothelial cells. Results Occludin protein was linearly expressed along brain vascular vessels. The expression of occludin protein at 3h was 0.35±0. 09 in brain tissues from rats with ANP and O. 49±0.08 in SO group, the expression of occludin mRNA were decreased from 1.50±0.30 to 1.01±0.18 （P 〈0.05）, the lowest expression rate occurred at 6 h, and the values in the two groups were 0.26 ±0. 07 and 0.93 ± 0. 19, respectively, the expressions of occludin protein and mRNA of ANP group at 12 h, 24 h were notably increased when compared with those at 6 h （ P 〈 0.05 ）, but they were still lower than those in SO group （ P 〈 0. 05 ）. The occludin protein and mRNA expressions were negatively related with the degree of panereatic pathologic changes （Pearson correlation coefficient ： - 0. 48 and - 0. 536, P 〈 0. 05）. Conclusions The expression of tight junction protein oecludin decreased at both protein and mRNA level in brain mierovascular endothelial cells of ANP rats. Furthermore, the expression of oeeludin was negatively correlated with pathological change of pancreas.