Effect of a mixture of pyrethroids at doses relevant to human consumption on general and male reproductive physiology in rats

Abstract

Humans are exposed to pyrethroid-based pesticides through agricultural produce. Consumption newlineof agricultural products that contain residual amounts of pesticides has become inevitable in the current newlineday world. Studies on the effects of unintentional intake of pyrethroid based pesticides that are akin to newlineactual human exposure settings are not reported. newlineMethods newlineDosages and choice of pyrethroids to be administered for animal experimentation were fixed newlinebased on: (1) the type and residual amount of pyrethroids present in rice and vegetables as per the report newlineof the Project Coordinating Cell, All India Network Project on Pesticide Residues, Indian Agricultural newlineResearch Institute, New Delhi 110 012; and (2) on the amount of rice and vegetables consumed by an newlineaverage Indian as per the report published by National Institute of Nutrition, Hyderabad, India. Basing newlineon these reports, it is estimated that the daily per kg body weight exposure to a mixture of pyrethroids newline(allethrin, cypermethrin, deltamethrin, cyhalothrin L, and fenvalerate) through rice and vegetables in an newlineaverage Indian is 15.695 and#956;g. The mixture of pyrethroids to be administered was prepared in corn oil. newlineThe duration of treatment was fixed on the basis of the fact that one month s lifetime in rat is newlineequal to 2.5 years in humans. We used rats that are 45 days old (1.5 months), whose age resembles newlineapproximately to that of 4-year-old humans. A 15-month treatment in rats is equivalent to 37.5 years of newlineexposure equivalent in humans. Thus, the duration of treatment is a direct reflection of the long-term newlineexposure of humans to pyrethroids through food on a daily basis starting from childhood stage to middleaged newlinelife. At different points after treatment (1, 3, 6, 9, 12, and 15 months), animals were sacrificed, newlinetissues collected, and further analyses conducted. newlineAnimal experimentation was conducted by two protocols. In the experimental protocol - I (EPI), newlinerats were treated daily for 9 to 12 months with a mixture of pyrethroids (allethrin, cypermethrin, newlinedeltamethrin,