Polaprezinc, a zinc compound, is distributed to the lingual epithelium and increases its zinc concentration in zinc-deficient rats.

摘要

AIMS: To clarify the mechanism underlying the effect of polaprezinc on hypogeusia, we investigated the uptake of polaprezinc by the tongue in rats. MAIN METHODS: Rats were fed a zinc-sufficient (Zn(+)) or zinc-deficient (Zn(-)) diet. After 4weeks on the Zn(-) diet, polaprezinc (1, 3, or 10mg/kg) or [(65)Zn] polaprezinc (10mg/kg) was administered orally once a day. The zinc concentration or the (65)Zn radioactivity of the tongue was measured by inductively-coupled plasma mass spectrometry or gamma counting, respectively. In addition, the distribution of (65)Zn in the tongue was analyzed by microautoradiography and the proliferative activity of taste bud cells was measured from the uptake of 5-bromo-2'-deoxyuridine. KEY FINDINGS: The zinc concentration of the lingual epithelium, but not the whole tongue, was markedly decreased in Zn(-) rats compared with Zn(+) rats. After administration of polaprezinc to Zn(-) rats at doses of 1, 3, and 10mg/kg, the zinc concentration in the lingual epithelium increased significantly from 85+/-4 to 105+/-7 (p<0.05), 120+/-3 (p<0.001), and 124+/-3 (p<0.001) microg/g, respectively. After administration of [(65)Zn] polaprezinc, the (65)Zn radioactivity of the tongue and serum were higher in Zn(-) rats than in Zn(+) rats. (65)Zn was mainly detected in the epithelium on microautoradiograms of the tongue in Zn(-) rats. In addition, polaprezinc (3 and 10mg/kg) improved the reduced proliferation of taste bud cells due to zinc deficiency. SIGNIFICANCE: Polaprezinc is distributed to the lingual epithelium and restores its zinc concentration in Zn(-) rats resulting in improvement of cellular functions, especially proliferation.