黄芩苷减轻放射诱导的大鼠肠纤维化

Baicalin alleviates radiation-induced intestinal fibrosis in rats

目的探究黄芩苷对放射致肠纤维化(radiation-induced intestinal fibrosis,RIF)大鼠的肠黏膜保护作用。方法用单剂量22.5Gy盆腔暴露构建大鼠RIF模型,然后连续4周分别通过灌胃法给予大鼠黄芩苷(200和400mg/kg/d)处理。在放射后第12周,用HE和Van Gieson染色观察直肠组织病理形态学变化;用免疫组织化学和Western blot检测直肠组织中α-SMA蛋白的表达;用免疫组织化学检测直肠组织中cleaved caspase-3和Ki-67分布与表达以评估直肠隐窝细胞的凋亡和再生能力;用免疫组织化学和RT-qPCR检测直肠组织中紧密连接蛋白claudin-3和occludin的蛋白和mRNA表达;用RT-qPCR分析直肠组织中促炎性因子TNF-α、IL-6和IL-1β的mRNA表达水平。结果黄芩苷能减轻放射诱发的大鼠直肠纤维化病变,降低放射导致的直肠组织中α-SMA和促炎因子TNF-α、IL-6和IL-1βmRNA表达的上调、直肠隐窝中cleaved caspase-3表达的上调和Ki-67表达的抑制、直肠上皮中claudin-3和occludin蛋白和mRNA表达的下调。结论黄芩苷能通过抑制放射所致的直肠组织中成纤维细胞向肌成纤维细胞的转分化、隐窝细胞凋亡的激活与增殖的抑制、紧密连接屏障结构的损伤和促炎因子表达的上调来缓解放射性辐射所致的肠纤维化损伤。

Objective To investigate the protective effect of baicalin on radiation-induced intestinal fibrosis(RIF)of intestinal mucosa in rats.Methods Rat RIF model was constructed by exposing the pelvis to a single dose of 22.5Gy,and then the rats were treated with baicalin(200 and 400mg/kg/d)by gavage for 4 consecutive weeks.At the 12th week after radiation,the histopathological changes of rectal tissues were observed by HE and VG staining;the expression of α-SMA in rectal tissues was detected by immunohistochemistry and Western blot;the distribution and expression of cleaved caspase-3 and Ki-67 in rectal tissues were detected by immunohistochemistry to evaluate the apoptosis and regeneration of rectum crypt cells;the protein and mRNA expressions of claudin-3 and occludin in rectal tissues were detected by immunohistochemistry and RT-qPCR,respectively;the mRNA expression levels of the pro-inflammatory cytokines TNF-α,IL-6 and IL-1β in rectal tissues were analyzed by RT-qPCR.Results Baicalin alleviated radiation-induced rectal fibrotic lesions in rats,and decreased radiation-induced upregulation of α-SMA and pro-inflammatory cytokines TNF-α,IL-6 and IL-1β mRNA expression in rectal tissues,upregulation of cleaved caspase-3 expression and inhibition of Ki-67 expression in rectal crypt,downregulation of protein and mRNA expressions of claude-3 and occludin in rectal epithelium.Conclusion Baicalin alleviates intestinal fibrosis injury induced by radiation in rats by inhibiting radiation-induced transdifferentiation from fibroblasts to myofibroblasts in rectal tissues,activating apoptosis and inhibiting proliferation of crypt cells,damaging tight junction barrier structure,and up-regulating pro-inflammatory factors expression.