Increased sensitivity to mitomycin C‐induced sister chromatid exchange in lymphocytes from patients undergoing hyperbaric oxygen therapy

Abstract

Treatment of cells with hyperbaric oxygen (HBO) results in the generation of reactive oxygen species and the induction of DNA damage. In the present study, we have evaluated the sister chromatid exchange (SCE) frequencies in lymphocytes from patients undergoing hyperbaric oxygen therapy (HBOT). In addition, we have determined the sensitivity of lymphocytes from those patients to SCE induction by 20 and 40 ng/ml mitomycin C (MMC). Patients undergoing HBOT for diabetic feet were exposed to 10 consecutive daily HBO treatments according to a routine therapy protocol. The study began with 12 patients; however, it was not possible to sample all of the patients at all HBOT sessions, and the number of patients gradually decreased towards the end of the HBOT. We observed a statistically significant induction in mean SCE/cell (P < 0.05; n = 11) immediately after the first session of HBOT. Relative to its frequency after the 1st treatment, the mean SCE frequency gradually decreased after the 5th and 10th HBOT sessions and reached baseline (pretherapy) levels 1 day after the last treatment in the four patients that were sampled. The mean MMC-induced SCE frequency was highest in lymphocytes sampled immediately after the first HBOT session, and significantly higher than the MMC-induced SCE frequency in cells sampled before HBOT. Unlike the case with untreated cells, MMC-induced SCE frequencies remained high in lymphocytes sampled at later stages of therapy and mean MMC-induced SCE frequencies were significantly higher (P < 0.05; n = 4) in lymphocytes sampled 1 day after the last session of HBOT than in lymphocytes sampled from these patients prior to beginning the therapy. The results indicate that HBOT induces SCE and that lymphocytes retain increased sensitivity to the genotoxicity of MMC one day after completing the HBOT.

Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation

“…Determination of the SCE frequency was performed by the method described previously (Duydu et al, 2006;Eken et al, 2005). Lymphocytes from 300 mL of blood were cultured in RPMI 1640 (Biological Industries, Israel) medium supplemented with 20% fetal calf serum (Seromed, Germany), 2% phytohemagglutinin (Sigma) and L-Glutamine (Sigma) and kept in the dark at 37 C for 72 hours.…”

Sensitivity to cisplatin-induced mutations and elevated chromosomal aberrations in lymphocytes from sickle cell disease patients

“…Many studies have reported that exposure to genotoxic agents, such as reactive oxygen species, influences the cytogenetic endpoints of cultured lymphocytes, and, in addition, it determines the sensitivity of lymphocytes in vitro from subjects exposed to genotoxic agents such as X-rays, ultraviolet light, bleomycin or mitomycin C [8][9][10]. The cytogenetic characterisation and classification of the different types of chromosomal aberrations in human peripheral blood lymphocytes have an important role in human genetics.…”

Increased Chromosome Fragility in Gastric Cancer Patients

“…MMC acts on the DNA and increases SCEs, induced in specific chromosomal regions, as it has been reported that MMC increases SCEs mainly at fragile chromosome domains (Wenger, 1995). MMC has been extensively used in chromosomal fragility studies in order to investigate if some conditions, such as diseases and various physical, chemical and biological agents affect its mutagenic efficiency (Latt et al, 1975;Ohtsuru et al, 1980;Duydu et al, 2006;Digkas et al, 2010 a ). The existence of sister chromatid exchanges (SCEs) connects to DNA replication, and their analysis is an excellent tool for the quantitative and qualitative evaluation of the DNA damage caused by physical, chemical or biological mutagenic agents (Lialiaris et al, 1987;Lialiaris et al, 2010;Digkas et al, 2010 b ).…”