Establishment Of A Model Of Graves' Disease By Immuning Syngeneic BALB/c Mice With HTSHR-activated Splenocytes

Objective:To obtain an animal model of Graves'disease by immune syngeneic BALB/c mice with human thyrotropin receptor-activated splenocytes. Methods:The female BALB/c mice, aged 6-8 week, were randomly divided into 2 groups (group a and group b) which were injected in the anterior tibialis muscle with recombinant plasmid PcDNA3.1/hTSHR and blank plasmid PcDNA3.1(+) respectively following pretreatment with bupivacaine and methyl-hydroxybenzoate. Injections were repeated 3 weeks and 6 weeks thereafter. The animals in both groups were sacrificed at 18 week and their spleen cells were mechanically disrupted. Other female syngeneic BALB/c mice (6-8 wks) were randomly divided into 2 groups (control and experiment). These mice were immunized into the tail vein with splenocytes from group a and group b respectively. The animals were killed at 4 weeks later, and their thyroids were carefully dissected out for light microscopy and electronic microscopy. In addition, a sample of blood was obtained from individual by extirpating eyeball for Total T4, TSH and TRAb assay. Results:44% experimental mice had goiters and hyperaemia as compared with control animals. The thyroid tissue microscopically displayed diffuse hypercellularity with colloid reduced and the follicular epithelia being tall cuboidal cells with irregular papillary poles protruding into the follicular space; there were minimal immune cells in the interstitium with slight hyperaemia and edema. Transmission electron microscope examination revealed that the follicular epithelia contained numerous mitochondria and rough endoplasmic reticula, and many long microvilli existed in the luminal surface. 2 of these mice had elevated serum total T4 with depressed TSH values and 3 had depressed TSH values without elevated total T4 according with the characteristics of hyperthyroidism and subclinical hyperthyroidism respectively. There was an increasing trend in serum TRAb value of experimental mice but without statistical significance(p>0.05). Conclusion:We have effectively induced an animal model that mimics some characteristics of human Graves'disease via spleen cells from syngeneic animals immunized with recombinant plasmid PcDNA3.1/TSHR. It provides a useful tool for further Graves'disease research including etiology, pathophysiology and therapeutics.