Effects of mastication on antibody production under fasting conditions in mice

Chewing is beneficial not only for digestion and absorption of food, but also for various physiological functions, such as cognition and immunity. In this study, the effect of chewing on hormonal changes and the immune response was investigated under fasting conditions in mice. We investigated leptin and corticosterone levels, which are hormones with well-known associations with immune response and large changes during fasting. To study of effects of chewing under fasting conditions, one group of mice was provided with wooden sticks to stimulate chewing, one group was supplemented with 30% glucose solution, and one group received both treatments. We examined changes in serum leptin and corticosterone levels after 1 and 2 d of fasting. Antibody production was measured 2 weeks after subcutaneous immunization with bovine serum albumin on the last day of fasting. Under fasting conditions, serum leptin levels decreased and serum corticosterone levels increased. Supplementation with 30% glucose solution during fasting increased leptin levels above normal, but had little effect on corticosterone levels. In contrast, chewing stimulation inhibited the increase in corticosterone production, but did not affect the decrease in leptin levels. Antibody production significantly increased under separate and combined treatments. Taken together, our results showed that chewing stimulation during fasting inhibited the increase in corticosterone production and improved antibody production after immunization.