Abstract
The effects of dehydroepiandrosterone sulfate (DHEAS) on thymocyte apoptosis induced by dexamethasone (DEX) were investigated. Apoptosis was measured by using agarose gel electrophoresis of DNA, the terminal deoxynucleotidyltransferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry. Our results showed that preincubation with 1 x 10(-4) M DHEAS protected thymocytes from DEX-induced apoptosis in vitro. Moreover, we found no blocking effect on the DEX-induced activation of caspase-3 and caspase-6 by the preincubation of thymocytes with DHEAS. This may be interpreted to mean that the antagonism of DHEAS to DEX-induced apoptosis is not related to the activation of these down-stream caspases which play a critical role in the execution of apoptosis.