IMPACT OF MATERNAL EXERCISE ON CORTICAL GEOMETRY AND TRABECULAR MICROARCHITECTURE IN MOUSE OFFSPRING

Exercise during gestation is safe and has many positive effects on the offspring, such as improved cardiovascular health and nervous system development. However, whether gestational exercise positively impacts skeletal development is unknown. PURPOSE: To determine whether maternal exercise throughout gestation and lactation positively impacts cortical geometry and trabecular microarchitecture of the femur in mouse male and female offspring. METHODS: In this longitudinal study, sexually mature C57BL/6 female mice were given ad lib access to a standard rodent chow. Two weeks before mating, females were randomized into two groups: voluntary wheel running treatment (EX) or sedentary control (SED). Females were mated to C57BL/6 males and continued treatment or control through both gestation and lactation. One male and one female offspring from each dam (n=7/group/sex) were selected and given ad lib access to a high-fat diet until 16 weeks of age, when final body weight was measured and femora collected. Cortical geometry of the mid-diaphysis and trabecular microarchitecture of the distal right femur were assessed via micro-computed tomography (μCT) with a voxel size of 12 μm. ANOVA or ANCOVA with final body weight (BW) as a covariate was used to determine the effects of maternal exercise on trabecular and cortical bone outcomes, respectively. RESULTS: There were no differences in BW between SED and EX male offspring. EX male offspring had smaller total area (Tt.Ar, p=0.075) and marrow area (Ma.Ar, p=0.025), and a higher cortical-to-total area ratio (Ct.Ar/Tt.Ar, p=0.017) compared to SED males. EX males had lesser trabecular thickness (p=0.049) but higher connectivity density (p=0.029) compared to SED. EX female offspring had greater BW than SED offspring (p=0.064). EX females had smaller Tt.Ar (p=0.017), Ma.Ar (p=0.033), and Ct.Ar (p=0.063) versus SED. EX female offspring had greater trabecular spacing (p=0.046) and degree of anisotropy (p=0.040), and lower trabecular number (p=0.034) compared to SED. CONCLUSION: Maternal exercise during gestation and lactation decreased cortical bone area independent of body weight and negatively impacted trabecular microarchitecture in both male and female offspring.