Effects of cypermethrin and methyl parathion mixtures on hormone levels and immune functions in Wistar rats

Abstract

To study interaction and dose-related effects of mixed cypermethrin and methyl parathion on endocrine and immune functions, 120 Wistar rats were divided randomly into six groups of ten male and ten female rats, respectively, at the age of 2 months. All groups were force-fed every 2 days for 30 days with cypermethrin 0.0, 8.0, 0.0, 8.0, 1.8, 0.4 mg/kg bw and methyl parathion 0.0, 0.0, 0.23, 0.23, 0.0518, 0.0115 mg/kg bw. Controls received vehicle solvent only. Body weight gain and organ weights were measured. Serum or blood were used to test luteinizing hormone, follicle stimulating hormone, estradiol (E(2)), testosterone, thyroid hormones (T(3), T(4), TSH), IgG, IgA, rate of neutrophil phagocytosis and of lymphocyte transformation. The effects on relative weights of ovaries and adrenals, IgA and rate of lymphocyte transformation were antagonistic interaction; the effect on estradiol was synergistic in female, whereas addictive in male rats; and the other indices indicated addictive interaction. Organ weights were similar in exposed and control animals except for adrenal (heavier in exposed rats, P<0.01). Serum levels of FSH and estradiol were higher in exposed groups than in controls (P<0.01). IgG levels were lower in exposed rats than in controls (P<0.01), and IgA levels were higher in exposed females than in controls (P<0.01). Lymphocyte transformation rates were lower (P<0.01) and neutrophil phagocytosis rates were higher (P<0.01) in exposed rats than in controls. Our results showed that exposure to low-dose mixtures of cypermethrin and methyl parathion may affect hormone levels (especially estradiol) and immune function in rats, and the NOAELs of combined compounds were located at 1/600 LD(50).

Fenvalerate Exposure Alters Thyroid Hormone Status in Selenium- and/or Iodine-Deficient Rats

“…Wang et al [43] observed a dose-dependent decrease in T 4 and T 3 and elevation in TSH in permethrin-treated rats; however, with deltamethrin, the only alteration was the decrease of T 4 levels. Similar results were observed with bifenthrin and Lambda-cyhalothrin [44], and recently, Liu et al [45] observed the same trend in Wistar rats treated with cypermethrin plus methyl parathion. These diverse results might be stemmed from the different study designs with respect to the dose, route, and length of insecticide treatment, as well as the sex, species, and strain differences of used animals.…”

In vitromyelotoxic effects of cypermethrin and mancozeb on human hematopoietic progenitor cells

“…Cypermethrin and mancozeb are the two widely used pesticides worldwide in agriculture, households, and industries due to their low mammalian toxicity and short environmental persistence (Hasan, 2010;Hayes & Laws, 1990;Lorgue & Lechenet, 1996). Cypermethrin is a synthetic pyrethroid insecticide which showed significant effects on hematological (Kamal et al, 2007;Nair et al, 2010;Sayim et al, 2005;Yousef et al, 2003) and immunological parameters (Desi et al, 1986;Liu et al, 2006;WHO, 1989) in sub-chronic repeated dose studies in animals. Mancozeb, ethylenebisdithio carbamate, is another pesticide used extensively and reported to have adverse effects on various hematologic (Myoung-yun & Cheong, 2004;Wael, 2012) and immunologic parameters (Corsini et al, 2005).…”

Analysis and evaluation of pyrethroid exposure in human population based on biological monitoring of urinary pyrethroid metabolites

“…Its low sensitivity in mammals ensures low acute toxicity. Recently, animal and in vitro studies suggest that some PYRs may disrupt the immune function, 50,51) produce oxidative stress, [52][53][54][55] and possess male reproductive toxicity by disrupting testosterone biosynthesis due to diminishing the delivery of cholesterol into the mitochondria and the conversion of cholesterol to pregnenolone in Leydig cells. 56) Moreover, it has been reported that the PYR metabolites, 3-PBAlc and 3-PBAld, possess estrogenic activity of approximately 10 5 less than that of 17b -estradiol.…”