Epithelial and stromal alterations in prostate after cypermethrin administration in adult albino rats (histological and biochemical study)

Association between pyrethroids and prostate endpoints; stratified according to renal function

BACKGROUND

Pyrethroids, one of the most commonly used pesticide classes, are considered to be selectively toxic toward insects rather than toward humans. However, there are accumulating data about pyrethroids toxicity in humans, especially sex organs. Thus, we investigated whether pyrethroids affected reproductive organs, especially the prostate gland.

METHODS

With 1305 subjects who participated in the National Health and Nutrition Examination Survey, several measurements were performed: 3-phenoxybenzoic acid (3-PBA), a common metabolite of pyrethroids; prostate-specific antigen (PSA); and other covariates. Both logistic and linear regression analyses were performed after stratifying according to kidney function, which was evaluated based on the estimated glomerular filtration rate (eGFR).

RESULTS

By logistic regression, the ORs (95% CIs) of the highest quantile to the reference group for higher total PSA were 2.039 (1.018 - 4.084) in the total study population and 2.219 (1.083-4.548) in the high eGFR group. The ORs (95% CIs) of the highest quantile to the reference group for a lower PSA ratio were 1.979 (1.057 - 3.707) in the total study population and 2.101 (1.086 - 4.064) in the high eGFR group. By linear regression, a marginally significant positive correlation between urinary 3-PBA and total PSA (β ± Standard Error = 0.049 ± 0.026, p = 0.0712) and a significant positive correlation between urinary 3-PBA and PSA ratio (β ± Standard Error = 0.018 ± 0.007, p = 0.0191) among the low eGFR group were observed.

CONCLUSION

This study showed that exposure to pyrethroids was associated with either increased levels of total PSA or alterations in the PSA ratio.

The influence of pyrethroides: permethrin, deltamethrin and alpha-cypermetrin on oxidative damage

Pyrethroids, synthetic derivatives of natural pyrethrins derived from Chrysanthemum cinerariaefolim, are commonly used for plant protection in the forestry, agricultural, pharmaceutical industry as well as in medicine and veterinary medicine. They can enter the body by inhalation, ingestion and skin contact. It was assumed that they are characterized by low toxicity to humans, are quickly metabolized and do not accumulate in tissues, and are excreted in the urine. Despite the existing restrictions, their use carries a great risk, because these compounds and their metabolites can get into the natural environment, contaminating water, soil and food. The consequences of using pyrethroids as a direct threat to animal and human health have been described for many years. They are published on an ongoing basis informing about poisoning with these compounds in humans and animals, and about fatalities after their taking. Children are most at risk because pyrethroids can be found in breast milk. These compounds have nephrotoxic, hepatotoxic, immunotoxic, neurotoxic effects and have a negative effect on the reproductive system and the fetus. Pyrethroids such as permethrin, deltamethrin, alpha-cypermethrin are approved by the World Health Organization for daily use; however, numerous scientific studies indicate that they can cause oxidative stress. They lead to DNA, protein, lipid damage and induction of apoptosis. The purpose of the work was to collect and systematize the available knowledge regarding the induction of oxidative stress by selected pyrethroids.

Pyrethroid based pesticides - chemical and biological aspects

Human and animal welfare primarily depends on the availability of food and surrounding environment. Over a century and half, the quest to identify agents that can enhance food production and protection from vector borne diseases resulted in the identification and use of a variety of pesticides, of which the pyrethroid based ones emerged as the best choice. Pesticides while improved the quality of life, on the other hand caused enormous health risks. Because of their percolation into drinking water and food chain and usage in domestic settings, humans unintentionally get exposed to the pesticides on a daily basis. The health hazards of almost all known pesticides at a variety of doses and exposure times are reported. This review provides a comprehensive summation on the historical, epidemiological, chemical and biological (physiological, biochemical and molecular) aspects of pyrethroid based insecticides. An overview of the available knowledge suggests that the synthetic pyrethroids vary in their chemical and toxic nature and pose health hazards that range from simple nausea to cancers. Despite large number of reports, studies that focused on identifying the health hazards using doses that are equivalent or relevant to human exposure are lacking. It is high time such studies are conducted to provide concrete evidence on the hazards of consuming pesticide contaminated food. Policy decisions to decrease the residual levels of pesticides in agricultural products and also to encourage organic farming is suggested.

Effect of long-term treatment with a mixture of pyrethroids on the expression of genes that govern male germ cell production in rats

Humans are exposed to pyrethroid-based pesticides through agricultural produce. In this study, male Wistar rats were orally treated for 9 to 12 months with a mixture of pyrethroids that is equivalent to one-fifth (high dose; HD) or one-twenty fifth (low dose; LD) of the amount of pyrethroids present in the cereals and rice consumed by an average Indian. In rats treated for 9 months, the spermatogenesis-associated genes Abp, Ar, Cd9, Dax1, Dazap1, Ddx3y, Gdnf, Gfra1, Grth, Inhb, Ovol1, P1, Plzf, Pygo2, Scf, Tgfb1, Tp1, Tp2, and Vim1 were downregulated in both LD and HD groups. In rats treated for 12 months Gdnf, Hsf2, Inhb, Tgfb1, Thy1, and Ybx2 expression was downregulated in both LD and HD groups. Steroidogenesis-associated genes 17-β-Hsd, Gata4, Hmgcr, Hmgcs1, Pde4b, and Tspo gene expression were reduced in both LD- and HD-treated groups treated for 9 months. In 12-month-treated rats, Creb1 expression decreased in both LD and HD groups. The epigenetic reprogramming-associated genes, Dnmt1, Dnmt3a, Dnmt3b, Hdac10, Hp1bp3, Kat3a Kat3b, Mch2ta, Ncoa7, and Sirt1 were downregulated in both HD and LD groups of 9-months-treated rats. In rats treated for 12 months, Hdac10, Mch2ta, Ncoa7, and Sirt1 messenger RNA levels decreased in both the HD and LD groups. Thus, we demonstrate that long-term exposure to a mixture of pyrethroids caused aberrations in the transcriptome of factors involved in sperm production and development.

Nephrotoxicity of cypermethrin in rats. Histopathological aspects

Cypermethrin (CYP) is an important type II pyrethroid pesticide widely used to protect crops against pests and insect infestations. However, its toxicity is a risk to both human health and the surrounding environment. The present study was conducted to investigate the nephrotoxic effect and histopathological changes caused by Cypermethrin in the kidney tissues of adult Wistar rats. In this study, 30 Wistar rats were equally divided into three groups. G1, control animals; G2 and G3 treated with various sub lethal doses of CYP for 30 days as follows: G2, administered low dose (1/100 of LD50) of CYP; G3, administered high dose (1/50 of LD50) of CYP. The damage to different organelles of renal proximal and distal cells was observed using transmission electron microscopy. Histopathological damage in kidney samples was confirmed using morphological and histological measures. The results showed that CYP caused significant histopathological damage to the renal proximal and distal tubules of treated rats. Compared to control samples, CYP caused marked alterations in the dimensions of nucleus, ovoid and filamentous mitochondria of the treated cells. In conclusion, Cypermethrin is found to be toxic to mammals. It caused marked ultrastructural damage to the renal proximal and distal tubules of Wistar rats and the intensity of nephrotoxicity correlated with the dose of oral administration.

Testosterone recuperates deteriorated male fertility in cypermethrin intoxicated rats

The present study investigates the protective effects of testosterone against reproductive toxicity induced by cypermethrin (50 mg/kg body weight) in rats. Significant reduction in the testicular and accessory sex organ weights were observed in cypermethrin-treated rats over controls. Cypermethrin intoxication significantly reduced testicular daily sperm count, epididymal sperm count, sperm motility, sperm viability and HOS-tail coiled sperm accompanied by significant reduction in the activity levels of testicular steroidogenic enzymes such as 3β- and 17β- hydroxysteroid dehydrogenases in rats as compared to controls. Further, qPCR studies indicated that the mRNA expression levels of steroidogenic acute regulatory protein (StAR) significantly decreased in cypermethrin-treated rats over controls. Molecular docking analysis indicated that the binding affinity of cypermethrin (- 11.2 kcal/mol) towards StAR protein was greater as compared to its natural ligand, cholesterol (- 8.2 kcal/mol) suggesting improper cholesterol channeling across the testis. Significant reduction in the circulatory levels of testosterone was also recorded in cypermethrin-exposed rats. An increase in pre- and post-implantation loss was observed in rats cohabited with cypermethrin-treated rats. On the other hand, testosterone (4.16 mg/kg body weight) treatment ameliorated cypermethrin-induced reprotoxic effects in rats. To conclude, cypermethrin-induced deterioration of suppressed reproductive performance in male rats could be linked to its antiandrogenic effects and on the other hand, testosterone-mediated protection of male reproductive health in cypermethrin-treated rats at least in part occurs via restoration of testosterone biosynthesis, spermatogenesis and sperm maturation events.