基于Wnt/β-catenin通路探讨黄芪多糖改善脾虚水湿不化大鼠肠黏膜损伤机制研究

The abnormal activation of Wnt/β-catenin pathway can cause gastrointestinal mucosal injury, decreased gastrointestinal function, it is closely related to the mechanism of syndrome of dampness retention due to spleen deficiency. In our previous studies，rats with syndrome of dampness retention due to spleen deficiency appeared decreased gastrointestinal function and intestinal mucosal injury； Astragalus Polysaccharide can improve gastrointestinal functions and intestinal mucosal injury, and significantly inhibits the expression of small intestine Wnt1. Therefore, we supposed that syndrome of dampness retention due to spleen deficiency might be related to gastrointestinal mucosal injury by the The abnormal activation of Wnt/β-catenin pathway，Astragalus Polysaccharide could inhibit the expression of Wnt1 through Wnt/β-catenin pathway，and then nourish qi to invigorate spleen and remove dampness. In this project, The expression and active of Key molecular and target genes in Wnt/β - catenin pathway will be detected in vivo and in vitro based on gastrointestinal mucosal, using immunohistochemistry, RT-PCR, etc, for clarifying the mechanism of nourish qi to invigorate spleen and remove dampness of Astragalus Polysaccharide.

Wnt/β-catenin 通路的异常激活可引起胃肠粘膜损伤，消化吸收功能下降，与脾虚水湿不化证发生密切相关。项目组前期研究发现，脾虚水湿不化大鼠胃肠功能显著下降，出现肠黏膜损伤；黄芪多糖可明显改善其胃肠功能和肠黏膜损伤，并显著下调了小肠Wnt1的表达。因此提出假说：“脾虚水湿不化证的发生与Wnt/β-catenin 信号通路的异常激活导致肠黏膜损伤有关，黄芪多糖通过抑制Wnt/β-catenin 信号通路，下调了wnt1的表达，改善肠黏膜损伤，发挥其益气健脾祛湿的功效。”本项目以肠黏膜损伤为切入点，基于脾虚水湿不化大鼠和体外原代培养的肠黏膜上皮细胞，采用免疫组化、RT-PCR 以及western blot 等多种方法检测Wnt/β-catenin 通路关键分子和靶基因的表达与活性，并采用Wnt抑制剂反证，为黄芪多糖益气健脾祛湿的机制研究提供新的研究思路和理论依据。

Wnt/β-catenin通路的异常激活可引起胃肠粘膜损伤，消化吸收功能下降，与脾虚水湿不化证发生密切相关。本项目提出假说：“脾虚水湿不化证的发生与Wnt/β-catenin信号通路的异常激活导致肠黏膜损伤有关，黄芪多糖通过抑制Wnt/β-catenin信号通路改善肠黏膜损伤，发挥其益气健脾祛湿的功效。”本项目以肠黏膜损伤为切入点，基于脾虚水湿不化大鼠和体外培养的大鼠肠黏膜上皮细胞，采用免疫组化、RT-PCR以及western blot等检测了Wnt/β-catenin通路关键分子Wnt1、β-catenin、CyclinD1、C-MYC的表达水平，并采用Wnt抑制剂反证，结果显示，脾虚水湿不化大鼠小肠粘膜损伤、胃肠功能下降、wnt1、β-catenin、CyclinD1、C-MYC蛋白表达异常升高，提示Wnt/β-catenin异常激活，诱发细胞发生增生性、炎性病变从而导致了肠黏膜上皮细胞损伤，因此推测肠黏膜损伤与Wnt通路异常激活有关。黄芪多糖通过抑制Wnt/β-catenin信号通路，下调了以上相关蛋白及基因的表达，改善了肠黏膜损伤及胃肠功能，发挥其益气健脾祛湿的功效。本研究为黄芪多糖益气健脾祛湿的机制研究提供新的研究思路和理论依据。