Characterization of thallium(III)-production of luminol chemiluminescence in Jurkat T cells

PUGA MOLINA, L. C.; VERSTRAETEN, S. V.

San Miguel de Tucuman, Tucuman

Congreso; XLV Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Trivalent thallium (Tl(III)) is highly toxic to humans through not well understood mechanisms. Among other effects, Tl(III) promotes an oxidative stress status in cultured cells. In the present work we investigated the possible origin of luminol’s chemiluminescence (CL) in Tl(III)-treated Jurkat T cells. Cells preincubation with free radical scavenger Trolox® did not affect the magnitude of the effect. In a cell free system, Tl(III) per se did not induce CL at pH 7.4. In the presence of H2O2, Tl(III) enhanced CL, in a Tl(III) (1-100 M)- and H2O2 (0.1-1 mM)- dependent fashion. In the absence of agitation, the reaction followed Belousov-Zhabotinski behavior, feature that disappeared under continuous agitation. Superoxide anion generation was evidenced, and the addition of superoxide dismutase decreased the magnitude of Tl(III)-H2O2 CL production. Only 40-60 % of added Tl(III) was recovered as Tl(I), suggesting that either Tl(III) acts as a catalyst of the reaction, or Tl(I) generated remains bound to luminol and could not be detected by the current methodology. Together, experimental results show that Tl(III) caused both in cultured cells and in a cell free system luminol CL, effect that depended on H2O2 presence. The rapid source of H2O2 in Tl(III)-treated Jurkat cells remains to be elucidated. Supported by grants of UBA (B086), ANPCyT (PICT 32273) and CONICET (PIP 112-200801-01977).