Orally administered brown seaweed-derived β-glucan effectively restrained development of gastric dysplasia in A4gnt KO mice that spontaneously develop gastric adenocarcinoma.

β-Glucan refers to a heterogeneous group of chemically defined storage polysaccharides containing β-(1,3)-d-linked glucose polymers with branches connected by either β-(1,4) or β-(1,6) glycosidic linkage. To date, an extensive amount of scientific evidence supports their multifunctional biological activities, but their potential involvement in the progression of premalignant lesions remains to be clarified. A4gnt KO mice that lack α1,4-N-acetylglucosamine-capped O-glycans in gastric gland mucin are a unique animal model for gastric cancer because the mutant mice spontaneously develop gastric cancer through hyperplasia-dysplasia-adenocarcinoma sequence. In particular, A4gnt KO mice show gastric dysplasia during 10-20 weeks of age. Here we investigated the putative gastro-protective activity of brown seaweed-derived β-glucan (Laminaran) against development of gastric dysplasia, precancerous lesion for gastric cancer in A4gnt KO mice. The mutant mice at 12 weeks of age were randomly assigned into three treatment groups namely, wildtype control + distilled water (normal control), A4gnt KO mice + distilled water (untreated control), and A4gnt KO mice + 100 mg/kg Laminaran. After 3 weeks, the stomach was removed and examined for morphology and gene expression patterns. In contrast to the untreated control group, administration of Laminaran substantially attenuated gastric dysplasia development and counterbalanced the increased induction in cell proliferation and angiogenesis. Furthermore, Laminaran treatment effectively overcame the A4gnt KO-induced alteration in the gene expression profile of selected cytokines as revealed by real-time PCR analysis. Collectively, our present findings indicate that β-glucan can potentially restrain the development of gastric dysplasia to mediate their tissue-preserving activity.