Effects of different zinc intake on mRNA expression of DMT1 in weaned mice

  Objective   To observe growth and development of the weaned mice fed with different levels of dietary zinc and to explore whether the expression of DMT 1 was induced by different dietary zinc intakes.

  Methods   Twenty weaned mice(postnatal day 21)were randomly divided into four groups: zinc deficient (ZD), zinc adequate (ZA), zinc supplemental (ZS)and pair fed (PF)were fed with different levels of dietary zinc for 3 weeks(from postnatal day 21 to postnatal day 42).The zinc contents in the diet of ZD, ZA, ZS and PF were 1, 30, 180 and 180 mg/kg respectively. Form postnatal day 21 to postnatal day 42, the dietary intakes and wieght of the mice were measured every day. On postnatal day 42(P42), the mice were sacrificed. Tissues were immediately isolated and the serumzinc concentrations were measured by AAS. The expression of DMT 1 was determined by semiquantitative RT-PCR.

  Results   The dietary intakes and weight of ZD mice were much lower than those of other groups. Serum zinc concentration in different groups changed significantly.DMT1 expression in test is declined significantly by higher zinc intake, but not in brain.

  Conclusion   A dequate dietary zinc was very important to growth and development of weaned mice.DMT 1 expression of testis was significantly downregulated by supplemental dietary zinc, which was supposed as the protective feed-back mechanism to maintain incellular zinc homeostasis of weaned mice.