Maternal corticosterone in the mouse alters oxidative stress markers, antioxidant function and mitochondrial content in placentas of female fetuses

Key points Maternal exposure to the stress hormone corticosterone is known to programme a range of sex specific disease outcomes in offspring. Sex differences in placental adaptations are thought to mediate these processes. Placental oxidative stress is implicated in a range of pregnancy disorders but the role of placental oxidative stress in sex specific disease outcomes following prenatal corticosterone exposure is unknown. This study demonstrates that maternal corticosterone reduced placental hydrogen peroxide and 8‐hydroxy‐2′‐deoxyguanosine concentrations but increased protein carbonyl content and advanced glycation end product concentrations in placentas of female fetuses but not male fetuses. These results highlight that placentas of female fetuses respond differently to maternal corticosterone exposure, with oxidative stress a major finding in placentas of female fetuses. Maternal exposure to glucocorticoids during pregnancy increases offspring risk of developing a range of sex specific disease phenotypes. These sex specific disease outcomes are thought to be in part mediated by different placental adaptations in males and females. The placenta is a highly metabolic organ which is vulnerable to the effects of oxidative stress. In other tissues, males and females have been shown to respond differently to the pro‐oxidant effects of glucocorticoids. This study therefore used a well characterized animal model of maternal corticosterone exposure to investigate sex specific alterations in reactive oxygen species production, antioxidant concentrations and mitochondrial properties that might contribute to sex differences in placental outcomes. C57BL/6 mice were implanted with osmotic minipumps containing corticosterone (33 μg kg−1 h−1) at embryonic day (E) 12.5 and placentas collected at E14.5 for analysis. Corticosterone exposure reduced placental hydrogen peroxide (H2O2) and 8‐hydroxy‐2′‐deoxyguanosine concentrations but increased protein carbonyl content and advanced glycation end product concentrations in placentas of female fetuses but not male fetuses. This dysregulation of different markers of oxidative stress may be due to increased placental activity of thioredoxin reductase in female but not male fetuses. Corticosterone reduced placental mitochondrial content but increased protein expression of the autophagosome cargo protein p62. This study demonstrates that placentas of female fetuses respond differently to maternal corticosterone exposure and h