【摘要】目的探讨肠源性尿毒症毒素同型半胱氨酸(homocysteine,Hcy)对腺嘌呤诱导的尿毒症大鼠肠道屏障结构功能的影响。方法SD 大鼠分为对照组(NC 组, n=10)、Hcy 组(H 组, n=10)、尿毒症(U 组, n=10)、尿毒症+Hcy (UH 组, n=10)和尿毒症+Hcy+益生菌(VSL#3, Sigma-Tau 公司，美国)(UHV 组, n=10)。腺嘌呤灌胃及皮下注射Hcy 造模，检测肾功能及病理组织染色评估动物模型。HE 染色及透射电镜观察肠道组织结构病理变化。检测血和肠组织Hcy、白细胞介素-6(interleukin, IL-6)、肿瘤坏死因子-α(tumor
necrosis factor, TNF-α)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde, MDA)水平、内毒素和肠道通透性。Western blotting 法检测紧密连接(tight junction，TJ)蛋白claudin-1、occludin 和ZO-1 水平。结果与NC 组相比，各组血清和肠组织匀浆中Hcy(血清F=153.666, P＜0.001；肠组织F=44.456,P＜0.001)、IL-6(血清F=86.845,P＜0.001；肠组织F=89.946，P＜0.001)、TNF-α(血清F=29.782,肠组织F=23.629, P＜0.001)、MDA(血清F=52.367, P＜0.001；肠组织F=58.976, P＜0.001)、血清内毒素水平(F=37.287, P＜0.001)和肠通透性(F=50.539, P＜0.001)显著增高，SOD 活性降低(血清F=106.538, P＜0.001；肠组织F= 114.599，P＜0.001)，以UH 组为著；UH 组肠道病理损伤最严重,各组TJ 蛋白水平不同程度降低。补充益生菌VSL#3 可不同程度上改善氧化炎症损伤并上调TJ 蛋白表达丰度。结论Hcy 通过诱导氧化炎症损伤，加重肠通透性增加和上皮屏障破坏。复合益生菌VSL#3可通过降低Hcy诱导的氧化炎症水平改善此损伤。
【Abstract】Aims To investigate the effect of intestinal-derived uremic toxin homocysteine (Hcy) on intestinal permeability, barrier structure and barrier function in adeninEinduced uremic rats. Methods SD rats were divided into five groups: normal control (group NC, n=10), Hcy (group H, n=10), uremia (group U, n=10), uremia+Hcy (group UH, n=10), and uremia+Hcy+ probiotic compound preparation VSL#3 (group UHV, n=10). Experimental uremia was induced by intragastric adenine administration and Hcy was injected subcutaneously. Animal models were assessed by renal function and pathological examinations. The pathological
changes of intestinal tissue were observed by H-E staining and electron microscopy. The levels of Hcy, interleukin (IL-6), tumor necrosis factor α (TNF-α), superoxide dismutase (SOD) and malondialdehyde (MDA) in serum and intestinal tissue, serum endotoxin, and intestinal permeability were assessed. The tight junction proteins of claudin-1, occludin, and ZO-1 were assessed by western blotting. Results Compared with group NC, serum and intestinal tissue levels of Hcy (serum: F=153.666, P＜0.001; tissue: F=44.456, P＜0.001), IL-6 (serum: F=86.845, P＜0.001; tissue: F=89.946, P＜0.001), TNF- α (serum: F=29.782, P＜0.001; tissue: F=23.629, P＜0.001), and MDA (serum: F=52.367, P<0.001; tissue: F=58.976, P＜0.001), serum endotoxin (F= 37.287, P＜0.001), and intestinal permeability (F=50.539, P＜0.001) were significantly elevated, while serum and tissue SOD activity decreased (serum: F=106.538, P＜0.001; tissue: F=114.599, P＜0.001) in the experimental groups, especially in UH group. The most pathological changes of intestinal structure were also found in group UH. The levels of tight junction proteins decreased in the experimental groups. Supplementation with probiotic compound preparation VSL#3 improved oxidative and inflammatory injuries and the expression levels of tight junction proteins. Conclusion Hcy aggravates the damages of intestinal permeability and epithelial barrier by induction of oxidative and inflammatory injuries in uremic rats. Probiotic administration
ameliorates these damages by reduction of Hcy-induced oxidative and inflammatory injuries.
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