Micronuclei induced in erythrocytes of Cyprinus carpio (teleostei, pisces) by X-rays and colchicine

Abstract

In the present work the induction of micronuclei in erythrocytes of Cyprinus carpio treated with X-rays and colchicine is studied for the evaluation of mutagenic effects of both clastogenic and mitoclastic (spindle poisoning) agents in this system.Three different experiments were performed treating groups of laboratory-reproduced animals with (1) single doses of X-rays (0.1, 0.5 and 2 Gy); (2) a single i.p. injection of colchicine at the concentrations: 1.6 × 10 −2 , 8× 10 −2 , 0.4 and 2 mg/kg b.w. so as to mimic an acute exposure to the agent and (3) six repeated i.p. injections of the first three concentrations of colchicine, over a period of 18 days, so as to mimic a chronic exposure. Repeated blood samplings were performed by cardiac puncture over a period of about 2 months after the treatment and micronucleus frequencies were determined at multiple times on the same individuals after mutagen exposure. A dose-dependent increase in the micronucleus frequency was observed in irradiated fish and a peak value detected at 21 days. Slight increases of micronucleus frequencies were also observed in both colchicine experiments only for the highest concentrations at the earliest sampling time. Higher concentrations of colchicine clearly showed a lethal effect. According to the present data the micronucleus frequency induced by the highest colchicine dose is comparable to that observed after 0.1 Gy of X-ray irradiation.

Perturbation of cytochrome P450, generation of oxidative stress and induction of DNA damage in Cyprinus carpio exposed in situ to potable surface water

“…MN are generated by segregational errors (due to clastogenic and/or aneugenic events) taking place in the dividing erythropoietic stem cells in the cephalic kidney. According to data from different authors, the estimated time for detection of MN in circulating blood erythrocytes ranges between the second and third week after a clastogenic treatment [9,10], which is compatible with the requirement of at least 100 days for a complete turnover of circulating erythrocytes.…”

“…Only nucleated erythrocytes with an intact cellular and nuclear envelope were scored. Rounded particles not larger than 1/5 of the main nucleus and without any connection to the nucleus were accepted as MN [10]. The scoring criteria were given in detail previously [9,10,43].…”

“…A number of organochlorine by-products (OBPs) have been shown to be non-genotoxic carcinogens in laboratory animals [5,6]. These compounds are also able to induce mutagenic effects in some biological systems such as bacteria [7], polychaete [8], teleost fish [9,10], mouse cells [11] and human B-lymphoblastoid cells [12]. Long-term studies in rats treated with the disinfectant sodium hypochlorite (NaClO) in drinking water showed an increase in leukaemia in female rats [13].…”

Modulating effects of humic acids on genotoxicity induced by water disinfectants in Cyprinus carpio

“…Based on radioisotope labelling experiments, an average lifespan of about 150 days has been estimated for red blood cells in Tinca tinca [47]. According to data from different authors, the estimated time for detection of MN in erythrocytes in circulating blood ranges from the 2nd and 3rd week after a clastogenic treatment [33,36,41], which is compatible with the requirement of at least 100 days for a complete turnover of circulating erythrocytes.…”

“…It has been employed for both in situ exposure to environmental waters [29][30][31][32][33] and laboratory treatments in vivo [33][34][35][36][37][38]. In particular, this test has been performed in Cyprinus carpio [18,[39][40][41].…”