IN-VIVO INDUCTION OF SISTER-CHROMATID EXCHANGE IN MOUSE BONE-MARROW FOLLOWING ORAL-EXPOSURE TO COMMERCIAL FORMULATIONS OF ALPHA-CYANO PYRETHROIDS

In vivo genetic toxicity potential of cypermethrin and deltamethrin, t wo alpha-cyano pyrethroid insecticides was evaluated through induction of sister chromatid exchange in mouse bone marrow cells. Groups of fo ur healthy, adult, male albino mice were each administered with a sing le oral dose of 10.6, 21.1 and 32 mg cypermethrin a.i./kg b.w. or 6.6, 13.2 and 20 mg deltamethrin a.i./kg b.w. in peanut oil. For reference , a peanut-oil vehicle control and cyclophosphamide (20 mg/kg, i.p.) p ositive control group of animals were run in parallel. Sister chromati d exchange (SCE) analysis in bone marrow metaphase chromosomes, 24 h p ost-treatment, revealed modest induction with statistical significance at the highest test dose of both insecticides as compared to the vehi cle control group. Further, the SCE induction by cypermethrin was more prominent than by deltamethrin. Marked induction of SCE frequency by exposure to cyclophosphamide, an alkylating mutagen, lent authenticity to these observations which, together with earlier evidence of mitoti c and chromosomal abnormalities by these pyrethroids, substantiated th eir genetic toxicity potential and susceptibility of mammals to conseq uent risks. (C) 1987 Elsevier Science Ireland Ltd.