The impact of a maternal and offspring obesogenic diet on daughter’s oocyte mitochondrial ultrastructure and bioenergetic responses. Insights from an outbred mouse model

This preclinical study used an outbred Swiss mouse model in a 2×2 factorial design to investigate how maternal and offspring obesogenic diets interact to affect daughter oocyte mitochondrial function. Female mice were fed a control or obesogenic diet for 7 weeks prior to breeding and then through gestation and lactation; their female offspring were fed the same diets for 7 weeks after weaning. The offspring obesogenic diet significantly increased oocyte lipid droplet content, mitochondrial activity, reactive oxygen species levels, mitochondrial ultrastructural abnormalities, and reduced pyruvate consumption, while mitochondrial DNA copy numbers and lactate production remained unaffected. The maternal obesogenic background caused a small but significant increase in offspring oocyte mitochondrial ultrastructural abnormalities without altering mitochondrial membrane potential, active mitochondrial distribution, or ROS production. Mitochondrial ultrastructure was the only outcome with a significant maternal-by-offspring diet interaction. The authors suggest that maternal diet-induced mitochondrial changes may be adaptive and compensatory, supported by reduced mitochondrial complex III and V expression and reduced pyruvate consumption, which could serve to control mitochondrial membrane potential and ROS levels.