Estabishment Of An Animal Model For Thyroid-Associated Ophthalmopathy By Immuming Homoimmune BALB/C Mice With HTSHR-Activated Splenocytes

Objective To establish an animal model for thyroid-associatedophthalmopathy(TAO) by immuning homoimmune BALB/c mice withhTSHR-activated splenocytes. Methods The female BALB/c mice(6-8wks)were randomly dividedinto group a and b which were immuned with recombinant plasmidpcDNA3.1/hTSHR and blank plasmid pcDNA3.1 for 3 times at 3-weekintervals respectively. Mice in 2 groups were sacrificed 18 wks afterimmunization and the splenocytes were isolated respectively. Other femalehomoimmune BALB/c mice(6-8wks)were divided randomly into group cand d which received splenocytes from group a and group b respectively.Four weeks later the orbital tissues were harvested for pathologicalexamination and serum was collected for TT4, TSH and TRAbmeasurements. Results After immunization with recombinant plasmidpcDNA3.1/hTSHR, orbital tissues displayed edema and mucinousdegeneration but no proliferation of adipose tissue and fibrous tissue in25% of mice (group a). After immunization with hTSHR-activatedsplenocytes, Orbital tissues microscopically displayed proliferation ofadipose tissues and fibrous tissues, degeneration and disruption of muscularfibers in 50% of mice (group c). Under electronic microscope, expansion ofsmooth endoplasmic reticulum and disorder of myofibrils are found inthese mice. In all of mice from group b and d, Orbital tissues displayednormal histology. After immunization with splenocytes, serum total T4levels were significantly elevated ( p=0.036 ) in mice of group c(7.130±1.017 ug/dl)when compared with group d (6.431±0.573 ug/dl),andserum TSH levels were significantly reduced(p=0.020)in mice of group c(0.070±0.032 uIU/ml) when compared with group d (0.098±0.020 uIU/ml).Two mouse displayed serology characteristics of hyperthyroidism with hightotal T4 and low TSH levels. Three mice displayed serology characteristicsof subclinical hyperthyroidism with normal total T4 and low TSH levels.Serum TRAb levels were slightly increased in mice of group c(0.202±0.067)compared to group d(0.151±0.055).But this differencewas without statistical significance(p=0.055). Conclusion The TAO animal model established by immuninghomoimmune BALB/c mice with hTSHR-activated splenocytes is verysimilar to human TAO in histological characteristics and is a feasible andreliable experimental method. Our study also proved that the thyrotropinreceptor and T cell aiming directly at this autoantigen played an importantrole in the autoimmune process of TAO.