Effect of tumor necrosis factor-α with different levels of iodine on expression of Na+/I- symporter in cultured lactating mammary cells / 中国地方病学杂志

ABSTRACT

Objective To observe the expression of Na+/I- symporter(NIS) in cultured lactating mammary cells with different levels of iodine and the effect of tumor necrosis factor-α(TNF-α). Methods Original generation of mouse lactating mammary cells cultured in vitro were divided into low iodine group Ⅰ (LI-Ⅰ), low iodine group Ⅱ (LI-Ⅱ), adequate iodine group(AI), high iodine group Ⅰ(HI-Ⅰ), and high iodine group Ⅱ(HI-Ⅱ). Cells were cultured in DEME/F12 culture medium for 24 h with different concentrations of iodine (0,5,50,3000 and 10 000 μg/L, respectively), and TNF-α( 10-2 mg/L) was added to some of cultured cells for 24 h. The expression of NIS mRNA of lactating mammary cells was determined by real-time quantitative PCR and the expression of NIS protein was detected by In-Cell Western. Results In iodine alone group, the expression of NIS mRNA in LI-Ⅰ group [ (64.66 ± 14.99) x 10-4] was higher than that of AI group[ (22.76 ± 7.36) × 10-4, P ＜ 0.01 ]; HI-I group[ (10.18 ±3.53) × 10-4] and HI-Ⅱ group[ (8.59 ± 2.89) × 10-4] were lower than that of AI group(all P ＜ .0.05); With increased iodine concentration, the expression of NIS mRNA decreased. The expression of NIS mRNA in LI-Ⅰ group [(2.72 ± 0.45) × 10-4], LI-Ⅱ group[ (2.69 ± 0.68) × 10-4] and AI group[(1.80 ± 0.67) × 10-4] with iodine plus TNF-o were all lower than that of LI-Ⅰ group, LI-Ⅱ group[ (29.82 ± 4.47 ) × 10-4], and AI group without TNF-α (all P ＜ 0.01). In iodine plus TNF-α, the expression of NIS mRNA in HI-Ⅰ group[(6.58 ± 2.87) × 10-4] and HI-Ⅱ[(7.04 ± 1.36) × 10-4] group were all higher than that of AI group(all P ＜ 0.05); With increased iodine deficiency or iodine excess, the expression of NIS mRNA increased. With increased iodine concentration, the expression of NIS protein decreased in iodine alone group. The expression of NIS protein in iodine plus TNF-α was all lower than that in iodine alone group. In iodine plus TNF-α, the expression of NIS protein increased in both iodine deficiency and iodine excess conditions. Conclusions Iodine may decrease the expression of NIS mRNA and protein of lactating mammary cells. The expression of NIS mRNA and protein of lactating mammary cells was inhibited by TNF-α under different levels of iodine.