RESUMEN
In the present paper, the protective effect of beta-carotene was evaluated after whole body exposure of mice to 2 Gy of X-rays. Splenocytes, reticulocytes, bone marrow cells and spermatids were evaluated for the frequency of micronuclei (MN) induced by X-rays. Mice were treated (gavage) with beta-carotene (10, 25 and 50 mg/kg b.w.) for 5 consecutive days and, 4 h after the last treatment, the animals were irradiated. The results obtained showed different frequencies of X-ray-induced-MN between different cell populations analysed and also different response of these cells to the beta-carotene treatment. The radioprotective effect of beta-carotene was observed in splenocytes, reticulocytes, and spermatids but not in bone marrow cells. No dose-response relationship for beta-carotene was detected. The time of sampling, the sensitivity of the cells as well as the antioxidant activity of beta-carotene are discussed as important factors for the radioprotective action of this provitamin.
Asunto(s)
Médula Ósea/efectos de los fármacos , Médula Ósea/efectos de la radiación , Protectores contra Radiación/farmacología , Reticulocitos/efectos de los fármacos , Reticulocitos/efectos de la radiación , Espermátides/efectos de los fármacos , Espermátides/efectos de la radiación , Bazo/efectos de los fármacos , Bazo/efectos de la radiación , beta Caroteno/farmacología , Animales , Células de la Médula Ósea , Masculino , Ratones , Pruebas de Micronúcleos , Bazo/citología , Irradiación Corporal Total , Rayos X/efectos adversosRESUMEN
The response of fully mature motile sperm and late spermatids when challenged with X-radiation at 0 degrees C has been studied in sex-linked recessive lethals, II-III translocations and dominant lethality experiments. At 0 degrees C a significant increase in both mutagenic and clastogenic damage was detected compared to that obtained at 24 degrees C. Furthermore, the results of experiments performed with different postirradiation temperatures demonstrate that the low temperature during irradiation was the sole factor responsible for the observed increase. In the recessive lethal and translocation tests the response of late spermatids was higher than that shown by motile spermatozoa. As a whole, the results, which are rather similar to data reported on the effect of irradiation in oxygen of the same cell stages, suggest that the low temperature acted as a dose-modifying factor.