菊粉增强小鼠肠道隐窝干细胞增殖能力促进放射性肠损伤修复OACHSSCD

Objective To investigate the protective effect of inulin against radiation-induced intestinal injury and its underlying mechanisms.Methods Male C57BL/6J mice aged 6-8 weeks were selected and randomly divided into eight groups(n=8 per group):normal control group,irradiation-only group,50 g/kg inulin group,100 g/kg inulin group,150 g/kg inulin group,50 g/kg inulin+irradiation group,100 g/kg inulin+irradiation group,and 150 g/kg inulin+irradiation group.After 5 weeks of corresponding feeding,mice in the irradiation group received whole-abdominal 10 Gy X-ray irradiation(radiation field covering from the xiphoid process to the pubic symphysis)at a dose rate of 1.17 Gy/min.The body mass of mice was monitored daily.On day 5 post-irradiation,small intestinal tissues of mice were collected.Colon length was measured to assess intestinal injury.HE staining was used to observe intestinal morphology.Immunohistochemical staining for PCNA and Ki-67 was performed to detect crypt cell proliferation.Immunofluorescence co-localization staining was employed to examine the co-expression of intestinal stem cell markers(Lgr5,Ascl2)and the proliferation marker Ki-67.qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels of intestinal stem cell markers under both irradiated and normal conditions.Results Compared with the irradiation-only group,50 g/kg inulin significantly alleviated body mass decline(P<0.05).Both 50 g/kg(P<0.01)and 100 g/kg(P<0.05)inulin mitigated colon shortening and improved intestinal villi injury(P<0.01)and crypt damage(P<0.01,P<0.05).Furthermore,they upregulated the expression of PCNA(P<0.01,P<0.05)and Ki-67(P<0.05).Immunofluorescence results showed that irradiation significantly reduced the number of Lgr5+and Ascl2+stem cells,suppressed Ki-67 proliferation signals,and caused obvious crypt structure destruction.Inulin intervention significantly restored stem cell fluorescence signal intensity and positive cell ratio,and enhanced the co-localization level between stem cells and proliferation markers,with better improvement observed in the 50,100 g/kg inulin groups.qRT-PCR indicated that inulin upregulated the expression of intestinal stem cell-related genes in irradiated mice(P<0.05).In normal mice,different doses of inulin differentially regulated stem cell markers and moderately enhanced the stemness of intestinal stem cells.Conclusion Inulin can promote the repair of radiation-induced intestinal injury by restoring intestinal stem cell numbers,enhancing their proliferative activity,and upregulating stem cell marker expression.It is also capable of regulating intestinal stem cell homeostasis in normal mice.