Early effects of iodine excess on spleen cells of methallothionein I/II knockout mice

Abstract

Objective To investigate the effects of iodine excess on spleen cell viability, lactate dehydrogenase (LDH) leakage, mitochondrial superoxide production and peroxiredoxin (Prx)3 expression in methallothionein Ⅰ/Ⅱ knockout (MT-Ⅰ/Ⅱ KO)mice. Methods Spleen cell suspensions were prepared from six to eight-week old and healthy male MT-Ⅰ/Ⅱ KO mice and wild type (WT) mice; the cell number was adjusted to 5 × 107/L and the cells were plated in 96-well plates (100 μl each well); the cells were exposed to various concentrations of KI (0, 10-4, 10-3, 10-2 mol/L) and 10-3 mol/L H2O2, respectively, for two hours, and control group did not give KI nor H2O2. Cell viability was assayed by methyl thiazolyl tetrazolium (MTT) colorimetric method. Cell damage was detected by chemical colorimetric method. Mitochondrial superoxide production in the spleen cells was measured by flow cytometry. Western blotting technology was used to investigate the expression of Prx3. Results In both MT-Ⅰ/Ⅱ KO and WT mice, the differences of cell viability, LDH leakage, mitochondrial superoxide production and the expression of Prx3 of spleen cells among the treatment groups were statistically significant (F = 357.92, 71.03, 130.36, 10.36, 179.58, 26.92, 187.43, and 7.16, all P 0.05). In 10-4, 10-3, 10-2 mol/L KI and 10-3 mol/L H2O2 treatment groups, cell viability of MT-Ⅰ/Ⅱ KO mice spleen was lower than that of WT mice (t = 6.47, 10.93, 9.30 and 4.96, all P < 0.05); LDH leakage was higher than that of WT mice (t = 4.30, 5.58, 5.56 and 4.13, all P < 0.05); mitochondria superoxide production was higher than that of WT mice (t = 4.64, 4.33, 2.80 and 2.52, all P < 0.05); Prx3 expression was higher than that of WT mice (t = 2.54, 2.37, 2.59 and 2.27, all P < 0.05). Conclusions KI may decline the cell viability, increase the leakage of LDH and increase the production of mitochondrial superoxide production and Prx 3 expression, which are much more significant in MT-Ⅰ/Ⅱ KO mice, suggesting that MT Ⅰ/Ⅱ has some antioxidative effect in high concentration of iodide induced oxidative stress in the spleen. Key words: Metallothionein; Iodine; Spleen; Superoxide; Mitochondria