ACTA ENDOCRINOLOGICA (BUC)

Context. The expression of TSHR-C on the serum tetraiodothyronine (T4) and TSH receptor antibody (TRAb) levels are rarely studied. Objective. The effect of TSHR-c on T4 and TRAb levels and concomitant thyroid histological changes in mice was investigated. Design. Animal experimental study. Subjects and methods. Female BALB/c mice at 6-8 weeks of age were immunized with the thyroid stimulating hormone receptor antigen C-terminus (TSHR-C), and randomly divided into control group (treated with the corresponding concentrations of normal saline) and four experimental subgroups: TSHR-c1 subgroup (4 μg), TSHR-c2 subgroup (6 μg), TSHR-c3 subgroup (8 μg) and TSHR-c4 subgroup (10 μg). Serum T4 and TRAb levels were determined. Results. The serum T4 level decreased significantly in the experimental mice as the concentration increased. All the experimental mice were positive for serum TRAb (experimental groups: 40 positive/40, 100% vs. control group: 3 positive/10, 30%) compared to the control group (P =0.000). HE staining showed that the follicles in the control mice were composed of small to medium-sized round follicles, whereas the follicles in the experimental mice were irregularly enlarged under light microscope. Conclusions. TSHR-c immunization resulted in thyroid hormone changes like those observed in hypothyroidism, probably due to the induction of TRAb generation.