To explore new methods of treating Graves′ disease (GD) by targeting thyroid stimulating hormone receptor (TSHR) and intercellular adhesion molecule-1 (ICAM-1).

The small interfering RNA (siRNA) targeting TSHR and the ICAM-1 monoclonal antibody (mAb) were designed and synthesized. Thirty GD model mice were randomly divided into siRNA treatment group, ICAM-1 mAb treatment group, and untreated GD group (10 mice in each group), and 10 normal mice were taken as blank control. Serum thyroxine (T₄), thyroid stimulating hormone (TSH), TSH receptor-stimulating antibody (TSAb) and TSH-stimulation blocking antibody (TSBAb) were measured before and after treatment. At the end of the treatment, body mass and heart rate of mice in each group were measured, and thyroid uptake of ⁹⁹Tc^mO₄^-, thyroid size and pathological changes were evaluated. Independent-sample t test, paired t test and one-way analysis of variance were used to analyze data.

After three treatments, the body mass of mice in siRNA group and ICAM-1 mAb group were significantly lower than that of normal mice (F=3.50, P=0.025); the heart rates of the mice in two groups were significantly lower than that of untreated GD mice (F=24.73, P<0.001). Heart rate of mice treated with siRNA decreased significantly, close to that of normal mice. After treatment, the serum T₄((27.58±1.94) vs (65.71±6.89) μg/L, (27.24±3.50) vs (70.84±8.46) μg/L), TSAb ((331.44±43.38) vs (457.33±45.85) mU/L, (275.16±45.80) vs (443.91±42.32) mU/L) and TSBAb ((13.94±1.11) vs (15.83±5.92) mU/L, (14.59±1.02) vs (17.05±6.16) mU/L) levels of mice in both siRNA group and ICAM-1 mAb group significantly decreased (t values: 4.45-10.87, all P<0.05), while the serum TSH levels of mice in two groups significantly increased ((0.13±0.05) vs (0.04±0.05) mU/L, (1.46±0.34) vs (0.06±0.03) mU/L; t values: -2.22, -5.87, P values: 0.007, <0.001). The elevated TSH level and decreased TSAb level of mice treated with ICAM-1 mAb were significantly different from those treated with siRNA (t values: 1.03, -1.63, P values: 0.002, 0.031). After treatment, the uptake of ⁹⁹Tc^mO₄^- in part of the thyroid lobes of mice was decreased, and the enlargement degree of the corresponding lobes was reduced. The thyroid pathology of mice in the treated groups showed that the absorption vacuoles of thyroid follicles were reduced, and the phenomenon of thinner colloids was improved. No obvious damage was observed in the heart, liver and kidneys of the mice.

Both the siRNA targeting TSHR and ICAM-1 mAb have therapeutic effects on GD model mice. The siRNA is better at controlling heart rate, and ICAM-1 mAb is better at increasing TSH and decreasing TSAb. Each of the above treatment methods is safe and effective, which can provide new ideas for GD targeted therapy.

Graves disease; RNA, small interfering; Receptors, thyrotropin; Antibodies, monoclonal; Intercellular adhesion molecule-1; Disease models, animal; Mice