Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB189

Poster Communications

The effects of antenatal hypothyroidism and voluntary exercise training on oxidative capacity and gene expression in soleus muscle of adult rats

A. Borzykh1, D. Gaynullina1,2, E. Selivanova1,2, A. Shvetsova1,2, D. Kostyunina1,2, I. Kuzmin1,2, A. Martyanov1,2, O. S. Tarasova1,2

1. Laboratory of exercise physiology, SRC RF Institute for Biomedical Problems RAS, Moscow, Russian Federation. 2. Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russian Federation.

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).

Where applicable, experiments conform with Society ethical requirements