G. F. IVANENKO, E. B. BUR L AKOVA
Copyright © 2013 SciRes. ENG
pheral blood lymphocytes, glutathione and lipid antioxi-
dant levels in blood plasma of people after the Chernobyl
accident.
2. Methods and Subjects
Children were examined from birth to the age of eight in
three regions with different levels of soil pollution with
radionuclides (largely 137Cs) after the Chernobyl accident.
Children (n = 125) from the Chechersk Region (15 - 20
Ci/km2) (Gomel Region of Belorussia) were examined 5
years after the accident; after six years children (n = 210)
from the Mtsensk Region (1 - 5 Ci/km2) and, after seven
years, children (n = 116) from the Bolkhov Region (5 -
10 Ci/km2) (both Orlov Region of Russia) were ex-
amined. Children at the age of 5 - 6 - 7 years (at the mo-
ment of examination) survived the accident during their
intrauterine development; other ones were born after the
accident (1990-1992).
Four years after the Chernobyl accident (1986), we
examined the liquidators (LI) that were working in the
first days after the accident and later moved to Slavutich
town outside the 30 km zone (n = 22). The radiation
doses of this group ranged from 2 to 150 cSv. Six years
later, we examined one more group of liquidators (L2, n
= 128) who worked fro m May 1986 to 1987 in the region
of Chernobyl accident and received radiation doses from
0.1 to 70 cSv. Were examined сhildren at the age 2 - 12
(n = 9) and of adults of Slavutich (n = 29) living in ra-
dionuclide-contaminated regions (1 - 5 Ci/km2). Resi-
dents of Moscow (n = 21) not exposed to radiation were
the comparison group.
The level of reduced and oxidized glutathione in plas-
ma was determined as described elsewhere [11,12] with
modifications. Glutathione level was determined in 20 -
100 µl plasma by spectrofluorometry at 350/420 nm. The
level of oxidized glutathione was calculated as the dif-
ference between the total numbers of SH groups before
and after the reduction using blank assays and standard
curves fo r GSH and G SSG . All results averaged for three
parallel experiments were expressed as µM. Tocopherol
and retinol were determined by spectrofluorometry at
295/325 and 330/470 nm, respectively, with appropriate
standards as desc ribed [13] .
The cytogenetic test relied on the traditional method
(analysis of unstable chromosomal aberrations). Whole
blood (0.5 ml) was cultivated as described by [14]. Both
chromosomal (dicentrics, centric rings, and paired frag-
ments) and chromatid (single fragments) aberrations
were evaluated. The fr equency of chr omatid b reaks (FC B)
calculated as a sum of single fragments (Fs), doubled
paired fragments (Fp), quadrupled dicentrics (Dc), and
rings (Cr) per 100 m e taphases .
Individual radiation doses of the Chernobyl liquidators
were determined as a total Chernobyl radiation loading.
Individual accumulated doses of radiation were deter-
mined from the age of children or as a total Chernobyl
radiation burden of their mothers before delivery. We
studied the effect of accumulated radiation dose of
mothers (Dm) after the Chernobyl accident on individual
cytogenetic and biochemical changes in peripheral blood
of their children.
3. Results and Discussion
Table presents the mean level of water-and lipo-soluble
antioxidants (GSH, vitamins E and A), oxidized gluta-
thione in blood plasma of adults and children living in
uncontaminated and radionuclide-contaminated regions
after the Chernobyl accident (1 - 20 Ci/km2 by l37Cs) as
well as of the liquidators with th e radiation doses from 2
to 150 and from 0.1 to 70 cSv (group s LI and L2, respec-
tively). Table demonstrates the absence of significant
differences in the studied indices in children and adults
living in regions with different radionuclide contamina-
tion. Only the liquidators (LI) had a significantly lower
GSH and a significantly higher level of GSSG in the
blood plasma as compared to all studied residents (Table
1). However, the stability of the blood plasma indices in
children from Mtsensk (1 - 5 Ci/km2), Bolkhov (5 - 10
Ci/km2), and Chechersk (15 - 20 Ci/km2) with different
levels of soil contamination by radionuclides was consi-
derably lower as compared to people from uncontami-
nated regions. The χ2 test demonstrated that GSH level
follows the Poisson distribution. Poisson variables have
particularly high coefficients of variatio n (CV).
Table 1 shows that the CV exceeds 40% for GSH in
children living in these regions. The highest individual
variability was observed in children from the Chechersk
region with the highest radionuclide contamination (15 -
20 Ci/km2); the corresponding CV reflecting variability
of the indices was equal to 82% for GSH and 67% for
vitamin A. Levels of tocopherol and retinol in children
from Chechersk region was significantly lower than in
residents of uncontaminated regions. In addition to lipo-
peroxidative stress, children of Chechersk had a three
time s higher levels of GSSG in the blood plasma in
comparison to Mtsensk and of Bolkhov residents (Table
1).
Apparently, the high individual variability of the stu-
died indices in children depends on radiobiological prop-
erties of ionizing radiation in case of long-term exposure
of their mothers to low-level radiation. We studied the
effect of accumulated total radiation doses of mothers
(Dm) after the Chernobyl accident on long-term changes
of biochemical and cytogenetic indices in their children
in comparison with the dose effects in the Chernobyl
liquidators.