Following up their earlier finding on the impact of CR on fertility in mice, the MGH team took a closer look at metabolic factors that may underlie those results. They first followed two groups of female mice from young adulthood (3 months of age) to 1 year, an age when egg quality and fertility normally would be greatly diminished. One group was allowed to free feed throughout adulthood, while the other was maintained on a CR diet for about seven months and returned to free feeding for the last month of the study period. While the free-fed mice showed the expected age-related decline both in the number of egg cells released at ovulation and in how many of those eggs were mature and ready for fertilization, the eggs cells of the aged CR mice more closely resembled healthy eggs of young adult females during their prime reproductive life.
Analysis of chromosomes and other meiosis-related aspects of the egg cells revealed significant abnormalities in cells from aged free-fed mice, while egg cells of the aged CR mice showed no evidence of aging-associated abnormalities. Since the age-associated decline in egg cell quality has been associated with changes in the distribution throughout the cytoplasm of mitochondria subcellular structures that provide cellular energy the researchers looked at the effects of diet on those cellular power plants.
|Contact: Sue McGreevey|
Massachusetts General Hospital