Induction
of DNA Primary Damage inPeripheral
Blood Leukocytes and
Exfoliated
Colorectal
Epithelial
Cells
in
Rats
Treated
with
Ozone
S.
Díaz-Llera,
Y.
González-Hernández,
J.E.
González
Mesa,
G.
Martínez-Sánchez,
L.
Re
SUMMARY - The in vivo genotoxic effect of ozone/oxygen mix (O2-O3) was studied in leukocytes and exfoliated colorectal cells of SD rats using the Comet assay (single cell gel electrophoresis assay, SCGE). O2-O3 (O3 final dose 42 g/kg b.w.) was applied for four days by colorectal insufflation simulating human ozone therapy. Bleomycin (15 mg/kg b.w., i.p.) was used as a positive control. The genotoxic effect of ozone was measured in exfoliated colorectal cells at 24, 48 and 72 h and in leukocytes at 0, 2, 6, 24, 48 and 72 h after the last exposure to O2-O3. As a result, a significant (p<0.025) increase in the primary DNA damage was observed in exfoliated colorectal cells and in the peripheral blood leukocytes. The highest values of DNA damage were observed at 48 h and 24 h after the last exposure to O2-O3 in exfoliated colorectal cells and in leukocytes respectively. However, 72 h after the last exposure a significant (p<0.05) decrease of DNA damage was observed in both cell types, indicating an evident recovery of the DNA primary damage induced by the treatment.