[The genotoxic effect of ciprofloxacin on cultured cells from the kangaroo rat kidney and on skin fibroblasts from the Indian muntjac].

The genotoxicity of an antibiotic ciprofloxacin (CF) in doses of 10, 25, 50 and 100 mkg/ml under its short-term (6-48 h) and long-term (15-30 days) action on sublines of Rat kangaroo kidney, NBL-3-11, and Indian muntjak skin fibroblasts has been studied. The emergence of genotoxic effect depends on the dose and time of ciprofloxacin action on both the sublines, but the degree of this effect does not depend on these parameters directly. Ciprofloxacin exerts no influence on cell distribution for chromosome number in subline NBL-3-11, and increases heterogeneity of this parameter in the subline of Indian muntjac skin fibroblasts in 30 days after its addition in doses of 25 and 50 mkg/ml. The degree of increase of chromosomal aberrations in the subline of Indian muntjak skin fibroblasts was in average 1.5 times more than in NBL-3-11 in all examined variants compared to the control. The minimum antibiotic dose that induced chromosomal aberrations was 25 mkg/ml in the subline of NBL-3-11 under a short-term action and 50 mkg/ml under a long-term action. For the subline of Indian muntjac skin fibroblasts the minimum inducing dose was 50 mkg/ml irrespective of the duration of action, except the case of 15 days, when the number of dicentrics increased still at 25 mkg/ml. In both sublines with the duration of ciprofloxacin action within 6-24 h the replacement of chromatid aberrations by chromosomal aberrations occurred. Under a long-term ciprofloxan action differences in types of chromosomal aberrations were discovered: for subline NBL-3-11 these were mainly chromosomal breaks; in the case of muntjac cells both chromosomal breaks and dicentrics (telomeric associations) occurred. The preferential involvement of some chromosomes in dicentric formation was observed. In cells of the muntjac subline, unlike NBL-3-11, the sensitivity of individual chromosomes to ciprofloxacin-induced breaks differed from that to spontaneous breaks. In both the sublines ciprofloxacin induces chromosomal breaks mainly in definite regions of chromosomes. Possible reasons of differences between the examined sublines towards the character of chromosomal instability are discussed in addition to the role of dicentrics as a proposed adaptation of cells to unfavourable factors of the environment.