“…In this study we have confirmed the ability of EIM to detect alterations in myofiber CSA, with the PolG animals most notably showing differences in the f c parameter, a value closely related to cell size. 24,25 Previous studies, 11,26 not using EIM, pooled male and female PolG mice to increase the statistical power based on a previous report indicating that there were no sex differences in mitochondrial oxygen consumption in the heart, skeletal muscle and liver, adenosine triphosphate content, mitochondrial H 2 O 2 generation, oxidative stress, and markers of apoptosis in WT mice of the same background. 27 However, here we found statistically significant differences in both con- In agreement with a previous study that evaluated EIM in a group of live 3-month-old and 25-month-old C57/B6 mice and showed an increase in both longitudinal and transverse f c in the aged mice, 8 in the present study we found a consistent increase in f c value in the untreated PolG mice, which correlates with the typical premature aging features associated with this model.…”