AIM: To investigate the effects of rhein on intestinal epithelial tight junction proteins in rats with IgA nephropathy (IgAN). METHODS: Twenty-eight female Sprague-Dawley rats were randomly divided into four groups (7 per group): Control, IgAN, Rhein-treated, and Rhein-prevented. Bovine serum albumin, lipopolysaccharide and CCl4 were used to establish the rat model of IgA nephropathy. The Rhein-treated group was given rhein from week 7 until the rats were sacrificed. The Rhein-prevented group was given rhein from week 1. Animals were sacrificed at the end of week 10. We observed the changes in the intestinal epithelial tight junctions using transmission electron microscopy, and expression of intestinal epithelial tight junction proteins zona occludens protein (ZO)-1 and occludin by immunofluorescence using laser confocal microscopy. Changes in mRNA and protein expression of ZO-1 and occludin were measured by reverse transcriptase polymerase chain reaction and Western blotting. The ratio of urinary lactulose/mannitol was measured by high performance liquid chromatography (HPLC) for assessing the intestinal permeability. RESULTS: In the control group, the tight junctions lied between epithelial cells on the top of the outer side of the cell membrane, and appeared in dense dotted crystal structures, the neighboring cells were binded tightly with no significant gap, and the tight junction protein ZO-1 and occludin were evenly distributed in the intestinal epithelial cells at the top of the junction. Compared with the control group, in the IgAN group, the structure of the tight junction became obscured and the dotted crystal structures had disappeared; the fluorescence of ZO-1 and occludin was uneven and weaker (5.37 ± 1.27 vs 10.03 ± 1.96, P vs 12.35 ± 4.17, P vs 0.92 ± 0.24, P vs 0.97 ± 0.25, P vs 1.98 ± 0.43, P vs 1.38 ± 0.31, P vs 2.72 ± 0.21, P vs 5.37 ± 1.27, P vs 4.23 ± 0.85, P vs 0.42 ± 0.19, P vs 0.40 ± 0.15, P vs 0.85 ± 0.12, P vs 0.72 ± 0.15, P vs 3.55 ± 0.68, P CONCLUSION: Rhein can enhance the expression of ZO-1 and occludin, repair damaged tight junctions, and protect the intestinal barrier.
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机译：目的：研究大黄酸对IgA肾病（IgAN）大鼠肠上皮紧密连接蛋白的影响。方法：将28只雌性Sprague-Dawley大鼠随机分为四组（每组7只）：对照组，IgAN，大黄酸治疗和大黄酸预防。用牛血清白蛋白，脂多糖和CCl 4 建立大鼠IgA肾病模型。从第7周开始，给予大黄酸治疗的组大黄酸，直至处死大鼠。大黄酸预防组从第1周开始给予大黄酸。在第10周结束时处死动物。我们使用透射电子显微镜观察了肠上皮紧密连接的变化，以及肠上皮紧密连接蛋白zona occludens蛋白（ZO ）-1和封闭蛋白通过激光共聚焦显微镜免疫荧光检测。通过逆转录聚合酶链反应和蛋白质印迹法测量ZO-1和occludin mRNA和蛋白表达的变化。尿乳果糖/甘露醇的比例通过高效液相色谱法（HPLC）测量以评估肠通透性。结果：在对照组中，上皮细胞之间紧密连接位于细胞膜外侧顶部，并呈致密的点状晶体结构，相邻细胞紧密结合，无明显间隙，且紧密连接蛋白ZO-1和occludin均匀分布在接合处顶部的肠上皮细胞中。与对照组相比，IgAN组的紧密连接结构变得模糊，点状晶体结构消失了。 ZO-1和occludin的荧光不均匀且较弱（5.37±1.27 vs 10.03±1.96，P vs 12.35±4.17，P vs 0.92±0.24，P vs 0.97±0.25，P vs 1.98±0.43，P vs 1.38±0.31 ，P对2.72±0.21，P对5.37±1.27，P对4.23±0.85，P对0.42±0.19，P对0.40±0.15，P对0.85±0.12，P对0.72±0.15，P对3.55±0.68，P结论：大黄酸可增强ZO-1和occludin的表达，修复受损的紧密连接并保护肠屏障。
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