Figure 2. Zinc-enhanced LPS-induced secretion of pro-inflammatory cytokines is mediated by intracellular zinc accumulation, P2X7 receptor activation, and reactive oxygen species generation.

(a–c) After microglia had been treated with or without 1 μM N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) for 30 min, followed by washing with warmed Eagle’s minimum essential medium and 2-h incubation with 60 μM ZnCl₂, they were treated with 1 ng/mL LPS for 22 h. (d–i) After microglia had been treated with or without 30 μM A438079 and 500 μM Trolox for 5 min, followed by 2-h incubation with 60 μM ZnCl₂ and one washout, they were treated with 1 ng/mL LPS for 22 h. The levels of interleukin-1 beta (IL-1β; a,d, and g), interleukin-6 (IL-6; b,e, and h), and tumour necrosis factor-alpha (TNFα; c, f, and i) were measured using enzyme-linked immunosorbent assays. Data are expressed as the mean ± the standard error of the mean (a–c, n = 3; d–i, n = 4). *p < 0.05, **p < 0.01, ***p < 0.005, significantly different from the control group; ^#p < 0.05, ^##p < 0.01, ^###p < 0.005, significantly different from the group pre-treated with zinc followed by LPS stimulation. LPS: lipopolysaccharide.