Cardiac Adaptation To Exercise During Pregnancy

Abstract

The extracellular composition and cardiac capillary density determine physiological from pathological cardiac hypertrophy. A number of studies demonstrate that exercise training does not increase fibrosis, whereas exercise training does increase capillary density and antioxidant capacity. However, whether exercise during pregnancy in previous sedentary dams could modify these parameters has not been investigated. METHODS AND RESULTS: 10 week old C57Bl/6 female mice were divided into non-pregnant diestrus control (C), late pregnancy (LP), and exercise during pregnancy (EX+LP). The EX+LP group was subjected to voluntary wheel running from gestation day 1 to 17. The pattern of running activity was high in early pregnancy and gradually decreased to low levels after mid-pregnancy. We found that both LP and EX+LP groups significantly increased heart mass normalized to tibial length (HW/TL). However, there were no differences in cardiac hypertrophy between LP and EX+LP. Next, we measured extracellular remodeling genes, angiogenic factors, and antioxidant related genes by quantitative real time PCR. mRNA levels of collagens, including Col1a1, Col3a1, and Col8a1, and connective tissue growth factor (Ctgf) were not altered in both LP and EX+LP groups compared to C. In addition, mRNA levels of angiogenic factors, including PGC-1α (Pgc1a), vascular endothelial growth factor a (Vegfa), angiogpietin-1 (Angpt1), Angpt2, fibroblast growth factor 2 (Fgf2), and platelet-derived growth factor alpha (Pdgfa) were not altered as well as antioxidant enzymes in both LP and EX+LP groups compared to C. CONCLUSION: Our results suggest that maternal exercise during pregnancy does not further increase pregnancy-induced cardiac hypertrophy. However, exercise during pregnancy may not be sufficient to activate the genes regulating angiogenesis and the antioxidant defense system.