Short-term zinc deficiency affects nuclear factor-kappab nuclear binding activity in rat testes.

We reported previously that feeding zinc-deficient diets for 14 d altered the oxidant defense system in the testes of young male rats and increased levels of lipid, protein and DNA oxidation in this tissue. In this study, we investigated the early involvement of oxidative stress in zinc deficiency-induced testicular pathology. Weanling male rats (17 d old) were given free access to a control (25 microg Zn/g) or a zinc-deficient (0.5 microg Zn/g) diet, or restricted access to the control diet at a level of intake similar to that of rats fed the 0.5 microg Zn/g diet (restricted group) for 7 d. Rats fed the low zinc diet were characterized by low testes zinc and alkaline phosphatase activity compared with ad libitum and restricted controls. Testes protein and lipid oxidation variables did not differ among the groups. Higher than normal (P < 0.05) activities of CuZn (CuZnSOD) and Mn (MnSOD) superoxide dismutases were observed in the low zinc group. Glutathione peroxidase and glutathione reductase activities did not differ among the groups. Total glutathione concentrations were lower in the low zinc and restricted groups than in the control group (P < 0.05). The testes nuclear binding activities of two transcription factors sensitive to oxidants [nuclear factor (NF)-kappaB and AP-1] were assessed. AP-1 nuclear binding activity did not differ among the groups, but NF-kappaB nuclear binding activity was lower in the low zinc group than in the control groups (P < 0.05). We suggest that the reduction in NF-kappaB binding reflects an early response to zinc deficiency-induced oxidative stress.