J Korean Soc Endocrinol.
2001 Oct;16(4-5):457-466.
The Changes of Expression of Thyroid Specific Antigens in Aging
- Affiliations
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- 1Department of Internal Medicine, Seoul National University College of Medicine.
- 2Department of Biochemistry, Seoul National University College of Medicine.
- 3Boramae Municipal Hospital.
- 4Clinical Research Institute Hormone Research Center, Seoul National University Hospital, Seoul, Korea.
Abstract
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BACKGROUND: With the prevalence of serum antithyroglobulin(anti-TG) and antithyroperoxidase(anti-TPO) autoantibodies increasing with age, it has been suggested that changes of thyroid autoimmunity with aging are associated with endemic iodine intake. To understand the mechanism of aging-related increases of thyroid autoimmune response, we investigated the expression of thyroid specific autoantigens of aged phenotype, and compared them with those of young phenotype both in vivo and in vitro.
METHODS
Sprague-Dawley rats were sacrificed at 5, 10 and 16 weeks(young), and at 23 months(aged). Their FRTL-5 thyroid cells were harvested at cell passages less than 10(fresh) or more than 30 (aged). The expression of thyroid autoantigens, sodium-iodide symporter(NIS), TSH receptor (TSHR), TG and TPO, were examined by northern blot analysis. To evaluate the effects of iodide, 1mM of NaI was added to the medium for 24 hours, and following incubation the expressions of MHC class I and class II were also examined.
RESULTS
The expressions of TPO were markedly increased in the aged rats, and those of TG were
moderately. However, NIS and TSHR showed no differences in their expression levels between aged rats and young rats. In vitro, there were no differences in the expressions of TG or TPO, nor of NIS or TSHR, between aged cells and fresh cells. Neither did Iodide exhibit any influence on the expression of MHC molecules in aged cells or fresh cells.
CONCLUSION
The expression levels of TPO and TG were increased in aged rats, which may partially explain the mechanism of increasing thyroid autoimmunity with age.