7、thymocytesdensityratioofcortextomedulladecreasedispositivecorrelationwithaging(p<0.05).theapoptoticlymphocyteofspleensoldagetakeplace.effectiveactivationofinadultgroupspleensaremuchincreased(p<0.05).conclusion:withageincreased,apoptosis is moreeasywit