CYTOGENETIC EFFECTS OF IONIZING RADIATION IN PERIPHERAL LYMPHOCYTES OF ISS CREW
MEMBERS (CHROMOSOME-2)
Research Area: Radiation Impacts on Humans
Expedition(s): 12- 16
Principal Investigator(s): ● Christian Johannes, PhD, University of Duisburg-Essen, Essen,
Germany
RESEARCH OBJECTIVES
Cytogenetic Effects of Ionizing Radiation in Peripheral Lymphocytes of ISS Crew Members
(Chromosome-2) is a continuation of the Chromosome-1 investigation. Chromosome-2
examines lymphocytes using different analytical methods to determine quantity and quality of
genetic changes resulting from exposure to cosmic radiation, particularly ionizing radiation.
From this study, scientists may be able to better assess risk factors for genetic damage in space
and help develop new methods for protecting crew members through strategies such as
radiation shielding, dietary supplements, pharmaceutical intervention, etc. Understanding and
reducing the risk of radiation is important for safe long-duration travel in space.
RESULTS
Frequencies of aberrant cells varied considerably between the experiment test subjects. An
aberrant cell is considered to include any type of aberration, eg, fragments, dicentrics, ring
chromosomes. The comparison of preflight and postflight scorings for individual crew members
revealed increasing values with no clear tendency. There was no significant difference between
short and long-duration crew members.
Most of the aberrations obtained in
preflight and postflight samples were
simple chromatid breaks. This aberration
type is not considered to be a marker for
radiation exposure. Dicentric chromosomes
and other interchanges that are considered
to be radiation indicators were found rarely
and showed no significant increase after
return from short- or long-mission flights.
The final result after scoring the remaining
samples will help to clarify this question.
Dicentric chromosomes are considered to
be the “gold standard” of radiation
exposure. This aberration type was only
found in a single postflight sample of a
long-duration crew member. The frequency of dicentrics was therefore not elevated above the
spontaneous level of unirradiated subjects.
The mBAND method is used to detect aberrations within
chromosomes as shown in the photo. An interstitial piece
is lost from one of the two chromosomes 5. University of
Duisburg-Essen image.