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No. 89 (PO 3)
Influence of masticatory dysfunction on antioxidant capacity in rat model
Maki Tanaka, Kageaki Kuribayashi, Daisuke Kobayashi, Naoki Watanabe
Department of Clinical Laboratory Medicine, Sapporo Medical University School of Medicine, Japan
Mastication is an essential function to maintain homeostasis of the animal. Disturbance in mastication
induces physical and psychological stresses. It has been elucidated that level of free radical, such as
superoxide, increases following physical and psychological stresses leading to various disorders,
including cancer and gastrointestinal ulcer. In this study, we investigated whether masticatory
dysfunction causes oxidative stress by changing feeding style from solid to liquid meal in rat model.
Neutrophils were collected from rats fed with solid or liquid meal, respectively, and superoxide
production was measured by cytochrome c reduction method. Serum superoxide dismutase activity was
evaluated using electron spin resonance spin-trapping technique. As a result, level of superoxide
production was higher in rats fed with liquid than solid meal. Furthermore, serum superoxide dismutase
(SOD) activity was lower in the former group. Decrease in serum SOD activity sustained from day 21 to
day 84 after meal was changed from solid to liquid meal. In rats fed with liquid meal, serum SOD
activity recovered to normal level 7 days after liquid meal was reversed to solid meal. These results
show that oxidative stress continues when mastication is disturbed. This study suggests that chewing
harmless solid materials, such as gum, may help avoiding unnecessary oxidative stress in patients
treated with liquid nutrition.
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