The effects of antenatal hypothyroidism and voluntary exercise training on oxidative capacity and gene expression in soleus muscle of adult ratsтезисы доклада
Дата последнего поиска статьи во внешних источниках: 11 апреля 2019 г.
Аннотация:Thyroid hormones are important regulators of skeletal muscle
growth and development. Therefore, thyriod deficiency during
early development may have long-lasting consequences for
muscle tissue characteristics in adulthood. The effects of antenatal
hypothyroidism (AH) may depend on muscle fibers type
and be important for muscle adaptation to aerobic exercise
training. The aim of this work was to explore the effects of AH
and voluntary exercise training in the soleus muscle from rats
with AH compared to control rats. We studied: 1) the oxidative
potential of muscle tissue (the contents of the mitochondrial
respiratory chain oxidative phosphorylation (OXPHOS)
complexes and citrate synthase mRNA), 2) myosin phenotype
(MHCs gene expression), 3) deiodinase 2 and thyroid hormone
receptor a1 genes, 4) activation and differentiation of satellite
cells (FOXO3A, MyoD and myogenin genes), 5) the activity
of catabolic pathways (MAFbx and MuRF-1 genes). To induce
AH, Wistar dams were given a solution of propylthiouracil PTU
(7 ppm) during the whole pregnancy and two weeks postpartum.
Six-week-old male offspring of control (CON) and
PTU dams were divided into sedentary control (CON, PTU)
and trained (CON-Tr; PTU-Tr) groups. The trained groups
had 24-hour access to the running wheels for 8 weeks (until
14-week age). T4 and T3 blood contents (ELISA) were reduced
in PTU vs CON at the age of 2 weeks, but no intergroup differences
were observed at 6 and 14 weeks. Total 8-week run
distance did not differ between CON-Tr and PTU-Tr groups.
The samples of soleus muscle were taken from 14-week old
rats and studied by Western blotting (for contents of OXPHOS
complexes) and by real-time PCR (gene expression). The
contents of OXPHOS complexes and MHC IIa mRNA were
less in sedentary PTU group than in sedentary CON. In control
rats, exercise training increased the contents of all OXPHOS
complexes, but only complex I was increased in PTU-Tr. Similarly,
in CON-Tr group, but not PTU-Tr group, we observed the
increases in citrate synthase, deiodinase 2, thyroid hormone
receptor a1 and MyoD mRNA expression levels. Along with
that, MHCI mRNA content was increased by training in
PTU-Tr but not changed in CON-Tr. The expression levels of
myogenin, FOXO3A, MaFbx and MuRF-1 were not affected
by training in either group of rats. Our data show that AH
reduces oxidative potential and fast MHC expression in soleus
muscle of adult rats. Importantly, the effects of training on
the oxidative potential and gene expression in soleus muscle
were generally suppressed by AH, in spite of unchanged level
of running activity. This study was supported by the Russian
Science Foundation (grant N14-15-00704).