title: 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.
authors.affiliation: Department of Toxicology, Faculty of Pharmacy, Ankara University, Tandodan, Ankara 06100, Turkey. duydu@pharmacy.ankara.edu.tr
authors.forename: Yalçin
authors.initials: Y
authors.lastname: Duydu
authors.forename: Aylin
authors.initials: A
authors.lastname: Ustündağ
authors.forename: Ahmet
authors.initials: A
authors.lastname: Aydin
authors.forename: Ayşe
authors.initials: A
authors.lastname: Eken
authors.forename: Kadir
authors.initials: K
authors.lastname: Dündar
authors.forename: Günal
authors.initials: G
authors.lastname: Uzun
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000737:chemistry; D002869:Chromosome Aberrations; D002877:Chromosomes, Human; D004249:DNA Damage; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000494:pharmacology; D008937:Mitomycins / Q000737:chemistry; D012680:Sensitivity and Specificity; D012854:Sister Chromatid Exchange; D013601:T-Lymphocytes / Q000378:metabolism; D013997:Time Factors
chemical_list: D000975:Antioxidants; D008937:Mitomycins; D016685:Mitomycin