Superfund Research Program

February 2024

Hot Publication

Prenatal exposure to the environmental contaminant benzene may have dose- and sex-dependent effects on several gene pathways in the brain and gonads, or sex organs, of adult zebrafish, according to research partly funded by SRP at Wayne State University. Because zebrafish and humans share certain genes, these findings may point to ways that prenatal benzene exposure affects humans.

First, the team immersed zebrafish embryos in water with low or high levels of benzene. They also placed a control group in water without benzene. After five days, they rinsed all embryos with water and allowed them to grow past sexual maturity in a tank of water. Next, the team extracted brain and gonad tissue from five male and five female fish from the control and experimental groups.

The researchers sequenced RNA from the tissues to analyze the zebrafishes’ transcriptome, the set of all RNA molecules coded by an organism’s genome. By comparing transcriptomes, they could determine if prenatal benzene exposure increased or decreased the expression of certain genes.

The team found that exposure to benzene during development affected the expression, or activation, of certain genes related to neurological development and disorders, reproductive ability, and cancer outcomes in both male and female zebrafish, regardless of benzene exposure level.

Within the low-benzene group, males showed more genes expression changes in gonad tissue, while females had more gene expression changes in brain tissue. However, in the high-benzene group, males demonstrated more gene expression changes than females in gonad and brain tissue alike.

The findings indicate that sex-dependent effects are associated with benzene exposure, even at low environmental levels, according to the authors. The study may also provide insight into long-term effects of benzene on human health and disease, they added.

To learn more, please refer to the following sources:

  • Connell ML, Wu C, Blount JR, Haimbaugh A, Kintzele EK, Banerjee D, Baker B, Baker TR. 2023. Adult-onset transcriptomic effects of developmental exposure to benzene in zebrafish (Danio rerio): evaluating a volatile organic compound of concern. Int J Mol Sci 24(22):16212. doi:10.3390/ijms242216212 PMID:38003401 PMCID:PMC10671089