Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland.
Med Sci Monit. 2011 Jan;17(1):BR16-26. doi: 10.12659/msm.881323.
The aim of this study was to assess the effect of diet supplementation with L-ascorbic acid (500 mg/L), tocopherol (3 mg/kg b.w.), and/or a water soluble analog of tocopherol (Trolox) (48 mg/L) on ion transport in the colon of rats subjected to a chronic exposure (9 months) to 0.1% lead acetate in drinking water.
MATERIAL/METHODS: The electrophysiological parameters of the colon wall were measured with Ussing methods. Lead content in the whole blood was analyzed by graphite furnace atomic absorption spectrometry (GFAAS) using Zeeman correction. L-ascorbic acid and tocopherol in plasma was measured by high performance liquid chromatography. Immunohistochemical reaction was carried out for visualization of occludin, the intracellular tight junction protein.
We showed a strong inhibitory effect of lead on the electrophysiological parameters, changes in intestinal permeability, disappearance of junctional occludin, decreased amount of mucus covering the colon surface, and the accumulation of PAS-positive substance in the apical region of the cytoplasm in the absorptive cells.
Supplementation with tocopherol or Trolox did not exert a beneficial influence on the studied parameters. L-ascorbic acid positively influenced the examined electrophysiological parameters, as it cancelled the inhibitory influence of lead on ion transport in the rat colon. L-ascorbic acid also protected against tight junction disruption of epithelial cells in the colon of the lead-treated rats. A similar effect was observed in the group of rats receiving lead and supplemented with L-ascorbic acid plus Trolox.
本研究旨在评估在慢性摄入 0.1%醋酸铅（9 个月）的大鼠中，饮食补充 L-抗坏血酸（500mg/L）、生育酚（3mg/kg bw）和/或生育酚水溶性类似物（Trolox）（48mg/L）对结肠离子转运的影响。
材料/方法：采用 Ussing 方法测量结肠壁的电生理参数。采用石墨炉原子吸收光谱法（GFAAS）并采用 Zeeman 校正分析全血中的铅含量。采用高效液相色谱法测定血浆中的 L-抗坏血酸和生育酚。通过免疫组织化学反应显示紧密连接蛋白 occludin。
我们发现铅对电生理参数、肠道通透性变化、连接蛋白 occludin 消失、覆盖结肠表面的粘液量减少以及吸收细胞细胞质顶区 PAS 阳性物质积聚有强烈的抑制作用。
生育酚或 Trolox 的补充并没有对研究参数产生有益的影响。L-抗坏血酸对所研究的电生理参数有积极影响，因为它抵消了铅对大鼠结肠离子转运的抑制作用。L-抗坏血酸还能防止铅处理大鼠结肠上皮细胞紧密连接的破坏。在接受铅补充 L-抗坏血酸和 Trolox 的大鼠组中也观察到类似的效果。
