Biochemical observations relating to oxidant stress injury in Chernobyl clean-up workers ("liquidators") from Latvia

To establish if there is further evidence for the long-term oxidant stress injury (as reported previously--Kumerova et al. in Biol Trace Elem Res 77:1-12, 2000) in surviving Chernobyl nuclear power plant (NPP) workers from Latvia. The overall objectives of this study have been to establish if there have been long-term systemic changes in the oxidant/antioxidant status of clean-up workers that might reflect adaptation to the progression of oxidative stress injury.

Biochemical analyses of the circulating levels of endogenous oxidants and anti-oxidants were undertaken over two periods (Stage 1 in 1998-1999 and Stage 2 in 2005-2006) at approximately 6-7 years time interval, in order to establish if there have been time-dependent changes in the parameters that may be important for the health of the clean-up workers. The biochemical analyses included (a) plasma levels of the anti-oxidant, selenium, (b) blood and plasma levels of glutathione peroxidase, (c) red blood cell catalase, (d) plasma total oxidant status as lipid peroxides and hydroperoxides, (e) plasma ceruloplasmin, and (f) total blood levels of zinc and copper.

The circulating content of lipid peroxides, plasma oxidisability, lipid peroxides, catalase, Zn, and Cu were elevated above normal values at both the stages of this study. Glutathione peroxidase was increased above normal values at Stage 1 but not at Stage 2. The most pronounced changes between Stage 1 and Stage 2 were (a) a reduction by about (1/2) in the content of lipid peroxides and lipid peroxidation, but not in the blood oxidisability and (b) increased plasma selenium. The data show that there may be a partial improvement in the anti-oxidant/oxidant status of the Chernobyl NPP workers over the 7-year period of investigation.

The NPP patients may be undergoing progressive reduction in blood oxidants accompanied by adaptation to oxidant stress injury due to the increased anti-oxidant activity measured in their plasma and blood.