Mercury induces in vivo and in vitro secretion of interleukin-1 in mice

Macrophages from SJL and DBA mice incubated with mercuric chloride (HgCl2) in vitro for 24-72 h secreted an increased amount of interleukin 1 (IL-1) to the supernatant compared with control-incubated macrophages, as determined by a sensitive thymocyte proliferation assay. The increase of IL-1 activity showed a highly significant dose-response relationship, being close to that in controls at 10(-8) M, and maximal after incubation with 10(-5)-10(-6) M HgCl2 in both strains. At optimal concentrations of HgCl2 the IL-1 activity started to increase after 6 hrs incubation and reached a maximum after 48 h. Incubation with concentrations of HgCl2 higher than 10(-5) M resulted in a severely reduced IL-1 activity, which correlated with a reduced cell viability. Extracts of HgCl2-incubated macrophages representing cell-bound IL-1 showed no increase in IL-1 activity, irrespective of the concentration or incubation time. Topical application of HgCl2 in a mixture of acetone-olive oil on the external ear of SJL mice induced a dose- and time-dependent increase in IL-1 activity. A maximal increase was seen after application of 1% HgCl2 for 24 h with lower IL-1 activity after 48 and 72 h. Application of 5%, but not 1% or 0.1%, slightly increased the IL-1 activity in the contralateral ear treated with acetone-olive oil only, as compared with the activity in ears from animals given no mercury treatment, suggesting a systemic effect by application of 5% HgCl2.(ABSTRACT TRUNCATED AT 250 WORDS)