1988 Fiscal Year Final Research Report Summary
The role of la antigen on thyroid epithelial cells in pathogenesis of autoimmune thyroiditis in BB/W rat.
| Project/Area Number |
61480253
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | SAITAMA MEDICAL SCHOOL |
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Principal Investigator |
ISHI Jun PROFESSOR, THE 4TH DEPARTMENT OF INTERNAL MEDICINE, SAITAMA MEDICAL SCHOOL, 医学部, 教授 (40049763)
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| Co-Investigator(Kenkyū-buntansha) |
TANIKAWA Toshinori RESEARCH FELLOW, THE 4TH DEP. INT. MED., SAITAMA MEDICAL SCHOOL, 医学部, 助手 (90167502)
KATAYAMA Shigehiro ASSISTANT PROF., THE 4TH DEP. INT. MED., SAITAMA MEDICAL SCHOOL, 医学部, 講師 (90167338)
KAWAZU Shoji ASSISTANT PROF., THE 4TH DEP. INT. MED., SAITAMA MEDICAL SCHOOL, 医学部, 助教授 (30134547)
HARA Yoshihito ASSISTANT PROF., THE 4TH DEP. INT. MED., SAITAMA MEDICAL SCHOOL, 医学部, 講師 (00112649)
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| Project Period (FY) |
1986 – 1988
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| Keywords | PATHOGENESIS OF AUTOIMMUNE THYROIDITIS / EXPERIMENTAL AUTOIMMUNE THYROIDITIS / BB RAT / IODINE METABOLIS / TSH RECEPTOR ANTIBODY / 甲状腺機能低下症 |
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| Research Abstract |
We have investigated on the pathogenesis of autoimmune thyroiditis (AIT) in BB/W rat with special interest in Ia antigen on thyroid epithelial cells. AIT began to develop from the age of 10 weeks and the incidence was about 60% at the age of 20 weeks. Focal and peri-vascular infiltration of lymphocytes and destruction of epithelial cells were the main histologic characteristics. The majority of the infiltrating lymphocytes had a helper/inducer phenotype and Ia antigen. However, thyroid epithelial cells did not show any Ia antigen at any age, which suggested that Ia antigen on thyroid cells did not have any pathogenic role in this animal model. Thyroid hormone levels in BB/W rat decreased with age and was more decreased in the rats with AIT than those without AIT. TSH levels were already high at the age of 8 weeks when AIT were not seen, suggesting the presence of an abnormality in thyroid hormone production from the period before AIT developed. Furhtermore, antithyroglobulin and anti -thyroid hormome antibodies were detected in the mojority of BB/W rat and began to appear before AIT developed. Therafore, it was speculated that abnormalities in thyroid gland itself resulted in early break down of immunological tolerance. We, then, sutdied on iodine metabolism in BB/W rat. Thyroidal radio-active iodine uptake and iodine content in thyroglobulin fraction were decreased in BB/W rat comparing to normal Wistar rat. TSH receptor antibodies were positive in one third of 16-weeks-old BB/W rat. However, the titers were low and there was no blocking activity against TSH action. Further studies on the abnormalities in thyroidal iodine metabolism are needed. From these studies, it is concluded that the abnormalities in the organ itself may be a factor for the pathogenesis in the organ specific autoimmune phenomena.
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