The in vitro antiapoptotic effect of dehydroepiandroesterone sulfate in mouse thymocytes and its relation to caspase-3/caspase-6

The effects of dehydroepiandrosterone sulfate (DHEAS) on thymocyte apoptosi s induced by dexamethasone (DEX) were investigated. Apoptosis was measured by using agarose gel electrophoresis of DNA, the terminal deoxynucleotidylt ransferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cyt ometry. Our results showed that preincubation with 1 x 10(-4) M DHEAS prote cted 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 mea n that the: antagonism of DHEAS to DEX-induced apoptosis is not related to the activation of these downstream caspases which play a critical role in t he execution of apoptosis.