Lifelong parental voluntary wheel running increases offspring hippocampal Pgc-1α mRNA expression but not mitochondrial content or Bdnf expression.

Abstract

When exercise is initiated during pregnancy, offspring of physically active mothers have higher hippocampal expression of brain-derived neurotrophic factor (Bdnf) and other plasticity-associated and mitochondria-associated genes, resulting in hippocampal structural and functional adaptations. In the present study, we examined the effects of lifelong parental voluntary wheel running (before, during, and after pregnancy) on offspring hippocampal mRNA expression of genes implicated in the exercise-induced improvement of cognitive function. C57BL/6 mice were individually housed at 8 weeks of age with (EX, n=20) or without (SED, n=20) access to a computer-monitored voluntary running wheel for 12 weeks before breeding. EX breeders maintained access to the voluntary running wheel throughout breeding, pregnancy, and lactation. Male offspring were housed in sedentary cages, regardless of the parental group, and were killed at 8 (n=18) or 28 weeks (n=19). PCR was used to assess mRNA expression of several genes and mitochondrial content (ratio of mitochondrial to nuclear DNA) in hippocampal homogenates. We found significantly higher peroxisome proliferator-activated receptor γ coactivator 1 α (Pgc-1α) mRNA expression in EX offspring compared with SED offspring at 8 weeks (P=0.04), although the effect was no longer present at 28 weeks. There was no difference in mitochondrial content or expression of Bdnf or any other mRNA target between offspring at 8 and 28 weeks. In contrast to exercise initiated during pregnancy, parental voluntary physical activity initiated early in life and maintained throughout pregnancy has little effect on offspring mRNA expression of genes implicated in exercise-induced hippocampal plasticity.