Guava seed polysaccharides ameliorate the inflammatory status in PC-3 xenograft mice

This work evaluates the effects of guava seed polysaccharide (GSPS) on inflammatory status in the experiment mice under PC-3 human prostate cancer stress for 4 weeks. Dietary control (DC group, 0 mg GSPS/kg BW/day), 50 (GL group), 250 (GM group) as well as 500 mg GSPS/kg BW/day (GH group) by gavage, positive control (PC group, 1 mg paclitaxel/week, i.p.) and non-treatment control (NTC group, normal mice without treatment) were designed in the experiment. Changes in tumor weights, serum non-specific antibody titers, Th1/Th2 cytokines secreted by splenocytes and pro-/anti-inflammatory cytokines secreted by peritoneal macrophages from the experiment mice were measured. As a result, GH group significantly (P < 0.05) decreased serum (IgM+IgA)/IgG ratio, but GL and GM groups slightly increased (IgM+IgA)/IgG ratios compared to that of DC group, demonstrating a differential effect on the serum antibody profile. Even though GSPS administration just slightly (P > 0.05) enhanced the effect to decrease tumor weights, there was a significantly (P < 0.05) negative correlation between tumor weights and (IgM+IgA)/IgG antibody titer ratios. GSPS administrations enhanced a Th2-inclined immune balance in splenocytes and anti-inflammatory responses in peritoneal macrophages in the experiment mice. Pro-inflammatory cytokine secretions by peritoneal macrophages were positively correlated with PC-3 tumor weights in vivo, inferring that anti-inflammatory cytokine secretions increased in vivo may decrease PC-3 tumor weight. Taken together, our results evidence that GSPS administrations ameliorated the inflammatory status in the experiment mice under PC-3 prostate cancer stress via regulating Th1/Th2 and pro-/anti-inflammatory cytokine secretion profiles toward Th2-inclined and anti-inflammatory immunity.