摘要：Lead inhibited the production of nitric oxide (NO) in cytokine-induced macrophage cell lines of RAW264 and Mm1. The decrease was revealed in the concentration of lead (0.1-10 μg/ml) which did not decrease the viability of these cells. The inhibition was proved to be due to the suppression of an inducible type of NO synthase (iNOS) mRNA expression in RAW264 cells. This suppression was found at 24 h and then recovered to the control level (stimulated with cytokine alone) following culture. In the RAW264 cell line, the time course pattern of NO production corresponded to the iNOS mRNA expression. From these results, the inhibition of NO production by, at least in part, mRNA level could be implicated in lead-caused abnormalities in immune functions.
