Effects of orally administered Euglena gracilis and its reserve polysaccharide, paramylon, on gastric dysplasia in A4gnt knockout mice.

Euglena gracilis is widely utilized as food or supplement to promote human and animal health, as it contains rich nutrients. In this study, we administered spray-dried powder of E. gracilis and paramylon, ß-glucan stored in E. gracilis cells, to A4gnt knockout (KO) mice. A4gnt KO mice are a mutant mouse model that spontaneously develops gastric cancer through hyperplasia-dysplasia-adenocarcinoma sequence in the antrum of the stomach, and we observed the effects of E. gracilis and paramylon on the early involvements of A4gnt KO mice. Male and female 10-week-old A4gnt KO mice and their age-matched wildtype C57BL/6J mice were orally administered with 50 mg of E. gracilis or paramylon suspended in saline or saline as a control. After 3-week administration, animals were euthanatized and the stomach was examined histopathologically and immunohistochemically. Gene expression patterns of the stomach, which have been reported to be altered with A4gnt KO, and IgA concentration in small intestine were also analyzed with real-time PCR and ELISA, respectively. Administration of Euglena significantly reduced the number of stimulated CD3-positive T-lymphocytes in pyloric mucosa of A4gnt KO mice and tend to reduce polymorphonuclear leukocytes infiltration. Euglena administration further downregulated the expression of Il11 and Cxcl1 of A4gnt KO mice. Euglena administration also affected IgA concentration in small intestinal contents of A4gnt KO mice. Paramylon administration reduced the number of CD3-positive lymphocytes in pyloric mucosa of A4gnt KO mice, and downregulated the expressions of Il11 and Ccl2 of A4gnt KO mice. Although we found no significant effects on gross and microscopic signs of gastric dysplasia and cell proliferation, the present study suggests that the administration of Euglena and paramylon may ameliorate the early involvements of A4gnt mice through the effects on inflammatory reactions in the gastric mucosa. The cancer-preventing effects should be studied with long-term experiments until actual gastric cancer formation.

Attenuation of carrageenan-induced hind paw edema and plasma TNF-α level by Philippine stingless bee (Tetragonula biroi Friese) propolis.

Despite decades-long existence of the Philippine stingless bee industry, the biological activity of propolis from this native bee species (Tetragonula biroi Friese) remains poorly understood and sparingly investigated. Herein, we examined the potential anti-inflammatory efficacy of Philippine stingless bee propolis using the lambda (λ)-carrageenan-induced mice model of hind paw edema. Thirty (30), six-week-old, male ICR mice were randomly assigned into three treatment groups (n=10/group) as follows: distilled water group, diclofenac sodium group (10 mg/kg), and propolis group (100 mg/kg). All treatment were administered an hour prior to the injection of the phlogistic agent. As observed at 3 h post-injection, λ-carrageenan remarkably evoked the classical signs of hind paw edema exemplified grossly by swelling and hyperemia. The ameliorative effect of propolis became apparent at the onset of 6 h post-injection with a statistically significant finding evident at the 24-h period. This gross attenuation histologically correlated to a considerable and specific reduction of the dermal edema, which mirrored those of the diclofenac sodium group. Furthermore, both propolis and diclofenac sodium significantly attenuated the λ-carrageenan-induced increase in the protein expression levels of the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) depicting more than two-fold decrement relative to the distilled water group. Altogether, these suggest that Philippine stingless bee propolis also exhibited a promising in vivo anti-inflammatory property, which can be partly mediated through the inhibition of TNF-α.

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

ß-Glucan refers to a heterogeneous group of chemically defined storage polysaccharides containing ß-(1,3)-d-linked glucose polymers with branches connected by either ß-(1,4) or ß-(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 ß-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 ß-glucan can potentially restrain the development of gastric dysplasia to mediate their tissue-preserving activity.