Effect of maternal hypothyroidism during pregnancy on insulin resistance, lipid accumulation, and mitochondrial dysfunction in skeletal muscle of fetal rats

The present study aimed to investigate the effect of maternal hypothyroidism during pregnancy on thyroid function of the fetal rat. Female Sprague–Dawley rats were randomized into two groups. Propylthiouracil (PTU) group received PTU in drinking water for 6 weeks (n=90), normal group received normal drinking water (n=50). The pregnant rats were obtained and had a cesarean-section to get at gestational ages of 8.5, 13, and 21 days, following blood samples and skeletal muscle were obtained from fetal rats. Levels of thyroid hormone, insulin, mitochondrial protein, and adipokines were detected using ELISA. Western blotting was performed to analyze mitochondria and insulin signal transduction-related protein in fetal rat skeletal muscle. Immunostaining of Periodic Acid-Schiff (PAS) and Oil Red O was used to observe the accumulation of muscle glycogen and lipid in the fetal rat. The results showed that the levels of thyroid hormone, insulin, insulin signal transduction-related protein, mitochondrial, and adipokines increased with the fetus developed, but had no statistical differences in the PTU group compared with the normal group. In conclusion, pregnant rats with hypothyroidism had no influence on insulin resistance (IR), lipid accumulation, and mitochondrial dysfunction in skeletal muscle of the fetal rats.