为探讨不同培养条件下伤寒沙门菌外膜囊泡(outer membrane vesicle，OMV)对结直肠癌细胞增殖的影响，本研究采用超速离心法分别提取伤寒沙门菌在正常、酸性、高渗、氧化环境LB液体培养基及LPM液体培养基中分泌的OMV，并比较其形态、粒径及所含蛋白大小。体外培养结直肠癌HT-29、SW480及CT-26细胞，采用CCK-8实验检测OMV对结直肠癌细胞增殖的影响，并用克隆形成实验进一步验证；采用流式细胞术检测细胞周期；通过统计体重及肝、肾组织苏木精-伊红染色切片评价OMV在小鼠体内的毒性。结果显示，不同培养条件下伤寒沙门菌分泌的OMV在形态、大小方面无明显差异，高渗应激环境下分泌的OMV更多。OMV所含蛋白相对分子质量在正常和酸性环境LB液体培养基中为37×10³～72×10³，在高渗和氧化环境LB液体培养基中为25×10³～72 ×10³，在LPM液体培养基中为8×10³～55×10³。LPM培养条件下OMV能显著抑制SW480和CT-26细胞的增殖，将SW480细胞周期阻滞于G2/M期，且对小鼠无明显肝、肾毒性。结果表明，LPM培养条件下OMV对结直肠癌细胞SW480、CT-26增殖具有直接抑制作用，有望成为结直肠癌治疗的新方案。

The aim of this study was to investigate the effect of outer membrane vesicle (OMV) of Salmonella enterica serovar Typhi (S. Typhi) on the proliferation of colorectal cancer cells under different culture conditions. Ultracentrifugation was used to extract OMV secreted by S. Typhi in normal, acid, hyperosmotic, oxidative LB medium, and LPM medium. The morphology, particle size and protein distribution of OMV under different conditions were compared. The colorectal cancer cells HT-29, SW480 and CT-26 were cultured in vitro. CCK-8 assay was used to detect the effect of OMV on the proliferation of colorectal cancer cells, and the colony formation experiment was used for further verification. The cell cycle was analyzed by flow cytometry. The toxicity of OMV in mice was evaluated through body weight and hematoxylin-eosin (HE) staining of liver and kidney tissues. The results showed that there was no significant difference in morphology and size of OMV under different culture conditions. Compared with other culture conditions, S. Typhi could secrete more OMV under hyperosmotic stress. In normal and acid LB medium the relative molecular weight of proteins in OMV was 37×10³—72×10³, in hyperosmotic and oxidative LB medium it was 25×10³—72×10³, and in LPM medium it was 8×10³—55×10³. OMV secreted in LPM medium could significantly inhibit the proliferation of SW480 and CT-26 cells, and arrest the cell cycle of SW480 cells in G2/M phase, without obvious hepatorenal toxicity to mice. It is concluded that OMV secreted by S. Typhi in LPM medium exhibit a direct inhibitory effect on the proliferation of colorectal cancer cells (SW480, CT-26), and it is expected to be a therapeutic drug for the treatment of colorectal cancer.