The impact of biomass smoke exposure during sperm maturation on the health of the father and their offspring.
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Firefighting has been associated with both testicular and prostate cancer, highlighting the potential sensitivity of the male reproductive tract to the varied chemical exposures in this occupation. In addition to these direct impacts on the reproductive health of males, such exposures may affect the health of their offspring through the epigenetic modification of sperm. To address these questions, we have developed a rat model of eucalyptus smoke exposure to represent a common biomass of Southern California wildland fires. In our studies, repeated smoke exposure (3 – 10 mg/m3) during the period of sperm maturation not only impaired motility but also altered non-coding RNA populations in caudal sperm (e.g., microRNAs and tRNA-derived RNA fragments). Furthermore, filtration of the particle phase of the smoke not only failed to protect against these alterations but also produced a greater decrement in sperm motility. Considering the influence that non-coding RNAs play in the transcriptomic landscape of the zygote and embryo, we next sought to understand the impacts of this paternal exposure on the cardiometabolic health of the offspring. In response to two different metabolic stressors (high-fat diet or heat), male offspring from smoke-exposed fathers (unfiltered) had worsened cholesterol profiles compared to unexposed controls. Furthermore, paternal smoke exposure also affected the immune status of both male and female offspring in adulthood. Increased circulating Th1 and Th2 cytokines were observed in these offspring, with exposure to elevated housing temperature inducing greater levels of interferon-gamma, interleukin 4, and interleukin 10. While additional work is underway to better characterize the full scope of the cardiometabolic, immune, and reproductive health of offspring borne from smoke-exposed fathers, data from our studies provide novel evidence of adverse generational health outcomes following relatively sub-acute smoke exposures in the male parent. This abstract does not reflect US EPA policy.