The effects of butylated hydroxytoluene on radiation and chemically-induced genetic damage in Drosophila melanogaster

Abstract

This paper reports the results of a study on the effects of the phenolic antioxidant butylated hydroxytoluene (BHT) on the sensitivity of Drosophila germ cells to the X-ray and chemical induction of genetic damage. Prior to irradiation or chemical treatment, the flies were raised in normal, BHT-containing or dimethyl sulphoxide (DMSO)-containing media. In one series of X-ray experiments, male pupae raised in these different media were irradiated. The concentration of BHT in the medium was 0.05% (in 0.5% DMSO) and that of DMSO, 0.5%. In the X-ray experiments, the frequencies of sex-linked recessive lethals and of autosomal translocations in spermatids of males raised in the BHT-containing medium were significantly lower than in those of males raised in the other two media. If however, the spermatids in pupae were irradiated, the amounts of genetic damage in the three groups of males were nearly the same. Likewise, no significant protective effects attributable to BHT treatment could be demonstrated with respect to the induction of dominant lethals in mature spermatozoa, stage-7 and stage-14 oocytes or of autosomal recessive lethals and sex-chromosome losses in stage-7 oocytes. In the dominant lethal experiments with mature spermatozoa and stage-7 oocytes, the yields were generally higher in males of the DMSO group than in the other two, pointing to a radiosensitizing effect of DMSO. In the ‘maternal effect’ experiments (males raised in a normal medium irradiated and mated to females raised in normal, DMSO-containing or BHT-containing media), the frequencies of dominant lethals in spermatozoa were similar in all the three groups, suggesting no DMSO- or BHT-mediated maternal effects. With both chemicals tested (diepoxybutane and diethylnitrosamine), significantly lower yields of sex-linked recessive lethals were recovered in spermatids of males raised in the BHT-containing medium than in those of males raised in the other two media. In some of these experiments, this protective effect of BHT was measurable in more advanced stages of spermatogenesis as well. These results have been interpreted taking into account the radical-scavenging, enzyme-inducing and enzyme-inhibiting properties of BHT.