title: Increase in number of annexin V-positive living cells of rat thymocytes by intracellular Pb(2+).
abstract: Lead is ubiquitous in our environment and lead poisoning is a major public health problem worldwide. In this study, to see if intracellular Pb(2+) induces the exposure of phosphatidylserine in rat thymocyte membranes, we have examined the effect of PbCl(2) on rat thymocytes treated with A23187 using a flow cytometer with appropriate fluorescent indicators under nominally-Ca(2+)-free condition. PbCl(2) at 1-30 μM dose-dependently induced the exposure of phosphatidylserine on outer membranes, associated with increasing the concentration of intracellular Pb(2+). The potency of intracellular Pb(2+) to induce the apoptotic change in thymocyte membranes seems to be greater than those of intracellular Ca(2+) and Cd(2+). Results suggest that intracellular Pb(2+) triggers apoptosis of rat thymocytes. This action of Pb(2+) may be one of mechanisms for the lead-induced changes in immunity.
authors.affiliation: Department of Life Sciences, Laboratories of Cellular Signaling and Environmental Physiology, Faculty of Integrated Arts and Sciences, The University of Tokushima, Minami-Jyosanjima 1-1, Tokushima 770-8502, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Nishizaki
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakao
authors.forename: Chisato
authors.initials: C
authors.lastname: Umebayashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Iwase
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tatsuishi
authors.forename: Masaya
authors.initials: M
authors.lastname: Satoh
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Oyama