Objective To establish in vitro the small intestinal organoid culture system and to investigate the effect of lipopolysaccharide(LPS)on the growth of small intestinal organoids and the secretion of inflammatory factors.Methods In vitro,the small intestinal crypt cell mass of C57BL/6 mice was aseptically isolated,collected and embedded in organoid matrix.Under the support of complete medium,the small intestinal organoids with three-dimensional multi-leaf structure with small intestinal epithelioid structure were formed.The small intestinal organoids were subcultured after 5-7 d culture.On the third day after passage,the small intestinal organoids were randomly divided into different mass concentrations of LPS groups(0,150,175,200,225,250,275 and 300 mg/L).After 24 h and 48 h of LPS induction,morphological changes of small intestinal organoid growth and differentiation were observed.CCK-8 method was used to detect the effect of different time points and mass concentrations of LPS on the proliferative activity of small intestinal organoids after induction of inflammation.The effects of four different mass concentrations of LPS(0,175,200 and 225 mg/L)on expression levels of granulocyte-macrophage colony stimulating factor(GM-CSF),interleukin(IL)-1α,IL-6 and IL-10 in organoid culture supernatant at different times were detected by enzyme-linked immunosorbent assay(ELISA).Results The mouse small intestinal organoid culture system was preliminarily constructed.After different time and mass concentration of LPS induced inflammation of small intestinal organoids,it was observed by morphology that small intestinal organoids would have different degrees of expansion and apoptosis in lumen.The proliferation,differentiation and budding of damaged intestinal epithelial crypts or intestinal stem cells were also inhibited to varying degrees,indicating that the growth of small intestinal organoids would be limited to varying degrees after induced inflammation.The proliferation activity of small intestinal organoids decreased to varying degrees after 24 h and 48 h of LPS induction at 175-225 mg/L(P＜0.05),but the cell viability was still greater than 50%.The levels of IL-1α,IL-6 and GM-CSF partially increased after induction with 200 mg/L and 225 mg/L LPS for 24 h and 48 h(P＜0.05).The level of IL-10 decreased after induction with 200 mg/L LPS for 24 h and 48 h(P＜0.05).Conclusion In this study,a model of intestinal inflammatory injury in vitro induced by LPS with different mass concentrations and time points is preliminarily constructed,which provides a more reliable research platform for the mechanism research of intestinal diseases and the screening of effective drugs in the future.