Expression data from mouse thymus

Previous studies have shown that extensive transciptional changes occur in the thymus as the tissue atrophies during aging, and that atrophy is delayed in catalase transgenic (mCat Tg, tg) mice. These studies address whether the transciptional profile of medullary thymic tissue in aged mCat Tg mice retains characteristics of the young medullary tissue or not. We used microarrays to detail transciptional profiles in aged mCat Tg mouse thymus to compare to gene expression in aged wild type mice. 12 month old mCat tg mouse thymi were snap frozen for RNA extraction and hybridization on Affymetrix microarrays. Whole medullary tissue from the middle third of the thymus was isolated by microdissection after snap freezing, 20 micron sectioning, fixation in acetone:ethanol, staining in ethanol:hematoxylin, and dehydration through graded ethanol, all done at ice cold temperatures.