Developmental Exposure of Lead Toxicity in Pregnant Mice


In this study, nine-week-old pregnant female rats were exposed to various concentrations of lead acetate while in their breeding and pregnancy stage via water intake. These young offspring from the female rats were not exposed to any other lead concentrations after the initial introduction to their mothers. Several tests were used to detect any significant changes in immunotoxicity when offspring are 13 weeks in age. Results showed that macrophage cytokine functions, which include NO2 production and tumor necrosis factor-alpha) were increased in the 250 ppm group. In this same group, cell-mediate immunity showed decreased levels. There were also higher levels of serum IgE in offspring of rats that received 100ppm. What’s surprising in this study is that the mothers that were initially given the lead acetate showed no chronic immune changes or physiological changes while the embryos showed significant detectable immunotoxicity levels, which further substantiates the hypothesis that lead exposure has higher immune sensitivity levels (specifically changing the balance between type 1 and type 2 responses) in embryos compared to that of adults.

This study was significant in its contribution to demonstrating how lead exposure in rats can cause immunomodulatory effects on offspring during development. This study can be comparable to the human model because some studies of lead toxicity in children have reported slightly lower blood lead concentrations than in mice that are reported to affect behavioral function. The most important finding is that offspring blood and bone of measured lead levels during the immune analysis were surprisingly low, which indicates that pregnant females and other species including humans, can pass defective immune function with even short-term exposure to lead.

Miller, T.E., Golemboski, K.A., Ha, R.S., Bunn, T., Sanders, F.S., Dietert, R.R. (1998) Developmental exposure to lead cause persistent immunotoxicity in Fischer 344 rats. Toxicology Science. 42(2): 129-35.

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