Study on the Therapeutic Mechanism of LXGYD on Intestinal Stem Cells and Tight Junction Proteins in GI-ARS Rats

Abstract:Background: Gastrointestinal acute radiation injury syndrome (GI-ARS) is potentially lethal and may occur after exposure to high radiation doses. Various chemical and biological agents have been developed to treat GI-ARS. However, their clinical utility is limited as they induce serious adverse reactions at their effective doses. Chinese herbal medicines have attracted attention because of their protective efficacy and low toxicity in radiation exposure treatment. However, their cellular and molecular mechanisms remain unknown. Here, we investigated the effects of the Chinese herbal Liangxue-Guyuan-Yishen decoction (LXGYD) on the intestinal stem cells and signal pathways of a GI-ARS rat model. Currently, there are limited treatment methods available globally; LXGYD might be a potential therapeutic option for patients with GI-ARS. Methods: The rat GI-ARS model was prepared by whole-body irradiation with 10-Gy of ⁶⁰Co-γ rays. Various LXGYD concentrations were intragastrically administered to the irradiated rats. Health status and survival of the rats were evaluated and the protective efficacy of LXGYD on the intestines was assayed by pathological analysis. The active principles in LXGYD were detected by liquid chromatography-mass spectrometry (LC-MS) and their potential targets and pathways were screened by network pharmacological analysis. Intestinal stem cell proliferation, intestinal epithelial tight junction (TJ) protein expression, and regulatory pathways were explored by immunohistochemistry (IHC), western blotting (WB), and real-time quantitative polymerase chain reaction (RT-qPCR), respectively.Results: LXGYD administration significantly improved health status and survival in GI-ARS rats. The pathological analysis showed that LXGYD ameliorated radiation-induced intestinal injury. The LXGYD infusion significantly promoted LGR5⁺ stem cell regeneration in the ileal crypts, upregulated TJ proteins, and accelerated crypt reconstruction in the irradiated rats in a dose-dependent manner. LC-MS revealed ≥ 13 LXGYD constituents that might contribute to its protective effects. Involvement of the WNT and MEK/ERK pathways in intestinal repair and recovery were screened by network pharmacology analysis and validated by western blotting.Conclusions: The present study disclosed a heretofore unrecognized role of the Chinese herbal LXGYD in rescuing the intestinal stem cells of a GI-ARS rat model. It also showed that the WNT and MEK/ERK pathways may be involved in LXGYD-mediated intestinal regeneration in GI-ARS.