An experimental study on the induction of Graves′ hyperthyroidism with Graves′ ophthalmopathy in BALB/c mice by TSHR gene immunization

Objective To construct a model of Graves′ disease(GD) with (or) Graves′ ophthalmopathy(GO) in BALB/c mice by immunization with pcDNA3.1/TSHR289. Methods pcDNA3.1/TSHR289 was injected into the bilateral gastrocnemius muscle of 35 model mice and electroporation was immediately performed. 10 control mice were injected with sterile saline and electroporated, while 5 blank mice were injected with sterile saline only. Each group of mice was immunized at 1, 4, 7, and 10 weeks, respectively. Serum total T4, TSH, TSAb, and TSBAb were measured before immunization, 2 weeks after each immunization, as well as 5 and 8 weeks after the last immunization. CT scan was used to evaluate the morphological changes of the eyes of the mice.99mTcO4- imaging was used to measure the thyroid uptake function, and the pathological changes of the thyroid and orbital tissues were evaluated by HE staining. Results After the 2nd time immunization, the serum concentrations of TT4, TSAb and TSBAb in GD mice were significantly higher than those of control and blank groups(F=13.781, 31.435, 36.112, P<0.01, respectively). The TSH continued to be significantly lower than that of control and blank groups(F=13.966, P<0.01). After the 4th time immunizations, the ability of uptaking99mTcO4- in GD mice thyroid was significantly enhanced compared with the control group. The thyroid goiter with a large amount of lymphocyte infiltration, and the thyroid follicle was thin. CT scan of GO mice showed thickening and swelling of the extraocular muscles, and no abnormalities in tendon and muscle attachment points. HE staining showed thickening of extraocular muscle fibers, lymphocyte infiltration of extraocular muscles and orbital tissue, increased hyaluronic acid, and infiltration of fat cells. Conclusion GD or GO model can be successfully induced by multiple intramuscular injection of pcDNA3.1/TSHR289 in BALB/c mice. Key words: Graves′ disease; Graves ophthalmopathy; TSHR; Mice models; Electroporation