Abstract
Abstract
Changes in zinc (Zn) metabolism and interleukin-1β (IL-1β) release occur as part of the physiological response to tissue injury and trauma. In the present study, the influence of Zn status on the response to continuous low-dose IL-1β administration was evaluated. Rats were fed 50 μg Zn/g (adequate zinc; AZn) or 5 μg Zn/g (marginal zinc; MZn) diets for 14 days. On day 15, rats were infused via osmotic minipumps, with IL-1β (2.3 ng/hr) or saline (control, C) and euthanized 1, 3, or 7 days later. In the AZn rats, IL-1β infusion resulted in increased plasma copper (Cu) concentrations and ceruloplasmin (Cp) activity, and decreased iron (Fe) concentrations throughout the 7d period. These effects were most pronounced on d1 and d3. A similar trend was observed in the MZn rats, but IL-1β-induced increases in plasma Cu and Cp activity were less than in the AZn fed rats. In MZn and AZn IL-1β infused rats, plasma Zn was decreased on Day 1, and Day 3, respectively, compared with their respective controls. AZn IL-1β-infused rats were characterized by high liver Fe, Zn, and metallothionein (MT) concentrations on Day 1; by Day 7, only MT concentrations remained elevated. Liver MnSOD activity was 13%–29% higher in both the AZn- and MZn-IL-1β-infused rats than their respective controls on Day 3 and Day 7, with most significant increase observed on Day 7. These data show that Zn status can influence the response to low-dose IL-1β; this influence of Zn should be considered when IL-1β is given therapeutically.
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