Pre-autoimmune thyroid abnormalities in the biobreeding diabetes-prone (BB-DP) rat: a possible relation with the intrathyroid accumulation of dendritic cells and the initiation of the thyroid autoimmune response

P. Simons
1998 Journal of Endocrinology  
Thyroid autoimmune reactions start with an accumulation of mainly dendritic cells in the thyroid. There is increasing evidence that, apart from being antigen-presenting cells, they are also able to control the growth and hormone synthesis of neighbouring endocrine cells. The questions thus arise: are dendritic cells accumulating in the pre-autoimmune thyroid in response to an altered proliferative or metabolic activity of thyrocytes, and do cytokines, monocyte chemoattractants, or both, have a
more » ... s, or both, have a role in their accumulation? We have investigated these questions in thyrocytes of the biobreeding diabetes-prone (BB-DP) rat in relation to the start of the intrathyroid accumulation of dendritic cells -that is, at about 9 weeks of age. BB-DP rats and Wistar rats (controls) were studied from 3 to 20 weeks of age. Hyperplastic goitre development was studied by assessing the thyroid weight and by measuring the number of thyrocyte nuclei per 0·01 mm 2 thyroid section. In addition, the in situ expression of interleukin-6 (IL-6), tumour necrosis factor-(TNF-), monocyte-chemotactic protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) were studied by immunohistochemistry. The in vitro proliferative capacity of BB-DP and Wistar thyrocytes was measured by tritiated-thymidine ([ 3 H]TdR) and bromodeoxyuridine (BrdU) incorporation into reconstituted, TSHand non-TSH-stimulated, cultured thyroid follicles. Further in vitro studies consisted of measurement of the production of thyroxine (T 4 ), triiodothyronine (T 3 ), thyroglobulin, IL-6, TNF-and MCP-1 by the thyroid follicles. BB-DP rats developed a small hyperplastic goitre between the ages of 9 and 12 weeks. The in vitro proliferative rate of thyrocytes isolated from hyperplastic BB-DP thyroids was significantly lower than that of Wistar thyrocytes. This phenomenon also occurred in Primary alterations in the BB rat thyroid · P J SIMONS and others
doi:10.1677/joe.0.1570043 pmid:9614356 fatcat:wcpk2jafbbey3cj3m7jpjpgavi