Abstract
Estrogen reduction is associated with a decline in skeletal muscle mitochondrial biogenesis.
Molecular events associated with improvements in markers of mitochondrial biogenesis
after resistance training and estradiol replacement are unknown. This study aimed
to investigate the effects of ovariectomy, resistance training, and estradiol replacement
on markers of mitochondrial biogenesis and protein expression related to oxidative
capacity in the rat gastrocnemius pool. Estradiol replacement was performed using
Silastic® capsules. During the 12-week resistance training, animals climbed a ladder with weights
attached to their tails. Gene expression was analysed by RT-PCR, and protein content
was determined by western blotting. Ovariectomy decreased the gene expression of the
mitochondrial biogenesis markers PGC-1α (~73%), NRF-1 (~44%), and TFAM (~53%) (p<0.05) and decreased the protein expression of phosphorylated AMPK, CREB and AKT,
which are related to oxidative capacity. Resistance training increased PGC-1α (~59%)
and TFAM (~48%) expression compared to the Ovariectomy-Sedentary group. The combination
of resistance training and estradiol replacement was superior to the ovariectomy-sedentary
and ovariectomy-resistance training treatments regarding the gastrocnemius muscle.
Estrogen deficiency altered the expression of genes and proteins that favour the development
of a mitochondrial dysfunction phenotype, which was improved with resistance training
and was partially improved by estradiol replacement.
Key words
mitochondrial biogenesis - ovariectomy - resistance training - skeletal muscle