Cardiovascular and growth outcomes of C57Bl/6J mice offspring exposed to maternal stress and ionizing radiation during pregnancy

Purpose: Developmental programming involves an adverse intrauterine environment which can result in offspring phenotype changes following birth. The developmental programming of hypertension has been reported to possibly involve oxidative stress at the cellular level. Ionizing radiation produces oxidative stress, even at low doses, and irradiation of animals is often coupled with potential sources of maternal stress such as transportation of animals or repeated handling. Materials and methods: Pregnant C57Bl/6J mice were irradiated on gestational day 15 with 5-1000 mGy ¹³⁷Cs gamma radiation. Post-natal weight, blood pressure (BP) and heart rate (HR) were measured. Radiation had minimal effects at doses ≤300 mGy, but 1000 mGy caused a significant reduction in HR in male pups and growth reduction at 16 weeks of age in both genders. The sham-irradiation protocol included repeated transportation in order to acclimate animals to transport. However, it may have resulted in programming, as sham-irradiation alone resulted in elevated BP measures compared to the offspring of animals that were never transported. Results and conclusions: Overall, there were minimal effects on cardiovascular measures or offspring weight due to irradiation except at 1000 mGy. The presence of maternal stress, a known trigger of developmental programming, may have confounded any potential irradiation effects.