Abstract:

BACKGROUND: Dendritic cells are the most important antigen presenting cells in vivo and play a double role of immune response and immune tolerance. There are more dendritic cells in thymus. With the increasing age of mouse, structure of mouse thymus shows degradation tendency, and the role of antigen-presenting dendritic cells is also reduced.
OBJECTIVE: To explore the morphologic change of different growth period mouse thymus.
METHODS: The thymus structures of the 4-week-old, 20-week-old and 10-month-old mouse were observed; dendritic cells occupied area percentage in the thymus were observed and analyzed by S100 immunohistochemistry and the dendritic cells density was calculated.
RESULTS AND CONCLUSION: Following age increasing, thymic cortex became thinning and the limit between cortex and medulla were more distinct. The glandular substance of 10-month-old mouse were obviously decreased and substituted with interstitial substance to be full of adipocytes. S100+ dendritic cells area and dendritic cells density in 20-week-old mouse were significantly higher than in 4-week-old mouse, but were decreased obviously in 10-month-old mouse (P < 0.01). Simultaneously, there were more S100+ macrophage on juncture between cortex and medulla in 10-month-old mouse thymus. Results demonstrated that, with age increasing, structure of mouse thymus trends to degradation; lower of antigen presenting effect of dendritic cells in gerontism mouse were closely related to reduction of quantity of dendritic cells.