Studies on reproductive toxicity of a pyrethroid, cypermethrin in albino mice

Abstract

The objective of the present study was to find out whether or not sub newlinelethal doses of cypermethrin (CYP), i.e.1.38, 2.76 and 5.52 mg/kg body weight newlinecorresponding to 1/476th, 1/238th and 1/119th of LD50 dose of aqueous newlinesuspension administered orally, adversely affect gametogenesis, sex steroid newlinesecretion, fertility, fertility indices, onset of puberty in progeny and accessory newlineorgans of male and female mice and if so whether effects are reversible or not. newlineThe work is divided into two chapters. First one deals with male toxicity and newlinesecond with female toxicity. newlineThree graded doses of CYP as mentioned above, were administered to newlineadult male mice orally through intubation on alternate day for two durations, 6 newlineweeks and12 weeks. There was a dose and duration dependent reduction in i) newlineweight of the body, testes and accessory reproductive organs, ii) serum levels newlineof testosterone, iii) total counts of epididymal spermatozoa whereas there was newlinean increase in abnormal sperm counts compared to controls. Despite these newlineeffects fertility and fertility indices were not affected.The effects of CYP newlinefollowing high dose (5.52 mg/kg body weight) treatment for 12 weeks were not newlinereversible whereas the condition was restored to normalcy in other doses newlinetreated mice within 6 weeks after cessation of treatment. newlineA similar regime of CYP administered i.e. doses and duration, in adult newlinefemale mice caused a dose and duration dependent reduction in, i) weight of newlinethe body, ovary and Fallopian tubes, ii) number of estrous cycles per month, iii) newlineserum levels of estradiol, iv) total number of healthy ovarian follicles whereas newlinethere was an increase in number of atretic follicles of all categories and weight newlineof the uterus compared to controls. There was a significant delay in onset of newlinepuberty and reduction in number of estrous cycles of progeny of medium and newlinehigh dose CYP treated mice mated with normal males.