Objective: Embryonic interferon-tau (IFNT) and progesterone affect expression of interferon-stimulated genes (ISGs), progesterone receptor (PGR) and progesterone-induced blocking factor (PIBF) in the ovine thyroid.
Methods: Thyroids of ewes were sampled at day 16 of nonpregnancy, days 13, 16 and 25 of pregnancy, and RT-qPCR assay, western blot and immunohistochemistry were used to detect expression of ISGs, PGR and PIBF.
Results: Free ISG15 protein was undetected, but ISG15 conjugated proteins upregulated at day 16 of pregnancy, and expression levels of ISG15 conjugated proteins, PGR isoform (70 kDa), PIBF, interferon-gamma-inducible protein 10 and myxovirusresistance protein 1 peaked, but expression level of signal transducer and activator of transcription 1 was the lowest at day 16 of pregnancy. In addition, the expression levels of PGR isoform (70 kDa) and STAT1 decreased, but levels of PGR isoform (43 kDa), 2',5'-oligoadenylate synthetase, IP-10 and MX1 increased at day 25 of pregnancy comparing with day 16 of the estrous cycle.
Conclusion: Early pregnancy affects expression of ISGs, PGR and PIBF in maternal thyroid through IFNT and progesterone, which may regulate thyroid autoimmunity and thyroid hormone secretion in ewes.
Keywords: Interferon-stimulated Gene; Progesterone Receptor; Progesterone-induced Blocking Factor; Sheep; Thyroid.