Abstract: The effect of polaprezinc, a chelate compound consisting of zinc ion
and L-carnosine, on abnormalities of taste sensation induced by feeding a
zinc-deficient diet to rats was examined by using the two-bottle preference
test (quinine hydrochloride as a bitter taste and sodium chloride as a salty
taste). Rats were fed either a zinc-deficient or a zinc-sufficient diet. The
zinc-deficient diet increased the preference for both taste solutions, while
polaprezinc (at doses of 3 and 10 mg/kg) restored the altered taste
preferences. We also evaluated the proliferation of taste bud cells using
5-bromo-2'-deoxyuridine (BrdU). The BrdU incorporation into taste bud cells was
significantly reduced in rats fed a zinc-deficient diet compared with rats fed
a zinc-sufficient diet (from 50.8% to 45.0%, p<0.05) and this reduction was
reversed by polaprezinc at doses of 1, 3, and 10 mg/kg, increasing to 50.2%,
53.5%, and 52.5%, respectively. These findings indicate that zinc deficiency
induces the delayed of proliferation of taste bud cells, while polaprezinc
improves cell proliferation. In conclusion, polaprezinc had a therapeutic
effect in a rat model of abnormal taste sensation. Its mechanism of action was
suggested to involve improvement of the decrease in taste bud cell
proliferation caused by zinc deficiency.
