Objective  To investigate the effect of astaxanthin on autophagy and apoptosis of AGS cell infected by Helicobacter pylori (Hp).

  Methods  The AGS cells of gastric epithelial cell line were infected by Hp. The infected cells were divided into control groupprocessed by dimethyl sulfoxide (DMSO), 10 μmol/L astaxanthin group, 20 μmol/L astaxanthin group and 50 μmol/L astaxanthin group. After 96 hours of grouping, expression of outer membrane protein (OMP) of Hp of cells was detected by immunofluorescence. The mRNA expressions of microtubule associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ), LC3-Ⅰ, Beclin1, B-cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2 related X protein (Bax) were detected by quantitative real-time PCR (qRT-PCR). The expressions of autophagy and apoptosis related proteins were detected by Western blot, and apoptosis was detected by TUNEL.

  Results  Hp was dispersed in AGS cytoplasm, and Hp was able to infect AGS cells successfully. Astaxanthin was able to inhibit the proliferation of Hp, and the apoptosis rates of 10, 20 and 50 μmol/L groups were significantly lower than those of the control group (P < 0.05). The protein and gene expressions of Beclin1, ratio of LC3-Ⅱ to LC3-Ⅰ (LC3-Ⅱ/LC3-Ⅰ) and Bax protein decreased gradually with the increase of astaxanthin concentration, while protein and gene expressions of Bcl-2 protein increased gradually with the increase of astaxanthin concentration, and there were significant differences when compared to control group (P < 0.01). The contents of interleukin-17 (IL-17) in 10, 20 and 50 μmol/L astaxanthin groups were significantly lower than that in the control group (P < 0.05), and the content of IL-17 decreased gradually with the increase of astaxanthin concentration.

  Conclusion  With the increase of astaxanthin concentration, the autophagy and apoptosis of AGS cells infected by Hp decrease.