Hepatotoxicity, Nephrotoxicity and Oxidative Stress in Rat Testis Following Exposure to Haloxyfop-p-methyl Ester, an Aryloxyphenoxypropionate Herbicide.

Ebenezer Olayinka,Ayokanmi Ore

doi:10.3390/toxics3040373

Abstract

Haloxyfop-p-methyl ester (HPME) ((R)-2-{4-[3-chloro-5-(trifluoromethyl)-2-pyridyloxy]phenoxy}propionic acid), is a selective aryloxyphenoxypropionate (AOPP) herbicide. It exerts phytotoxicity through inhibition of lipid metabolism and induction of oxidative stress in susceptible plants. This study investigated the toxicological potentials of HPME in rats. Twenty-four male Wistar rats (170–210 g) were randomized into four groups (I–IV). Group I (control) received 1 mL of distilled water, while animals in Groups II, III and IV received 6.75, 13.5 and 27 mg/kg body weight HPME, respectively, for 21 days. There was a significant (p < 0.05) increase in renal and hepatic function biomarkers (urea, creatinine, total bilirubin, ALP, ALT, AST) in the plasma of treated animals compared to control. Levels of testicular antioxidants, ascorbic acid and glutathione, and activities of glutathione-S-transferase, superoxide dismutase and catalase were reduced significantly after 21 days of HPME administration in a dose-dependent manner. The testicular malondialdehyde level increased significantly in the HPME-treated rats relative to the control. A significant decrease in testicular lactate dehydrogenase, acid phosphatase and γ-glutamyl transferase was also observed in HPME-treated animals. Testicular histology revealed severe interstitial edema and sections of seminiferous tubules with necrotic and eroded germinal epithelium in the HPME-treated rats. Overall, data from this study suggest that HPME altered hepatic and renal function and induced oxidative stress and morphological changes in the testis of rats.

Highlights

In the course of the last decade, applications of pesticides have increased steadily in Nigeria and in most developing countries as part of the effort to improve food production
The activities of the marker enzymes alkaline phosphatase (ALP), ALT and AST increased significantly in the plasma of Haloxyfop-p-methyl ester (HPME)-treated animals compared to the control
The activity of ALP increased by 35%, 46% and 67%, respectively, in the groups given 6.75, 13.5 and 27 mg/kg bw HPME, respectively

Summary

Introduction

In the course of the last decade, applications of pesticides have increased steadily in Nigeria and in most developing countries as part of the effort to improve food production. Occupational exposure to these compounds may occur in agricultural workers, workers in the pesticide industry and retailers of the products from improper handling [2]. Some of the commonly-reported adverse effects of human and animal exposures to herbicides include oxidative stress, immunomodulation, disruption of reproductive functions [3] and histopathological alterations in vital organs [3]. Most of the widely-applied herbicides in Nigeria include the derivatives of aryloxyphenoxypropionates (AOPPs) [4], including haloxyfop-p-methyl ester (Figure 1). Haloxyfop-p-methyl ester (HPME) is employed for the control of broadleaf and grassy weeds in corn, sorghum, sugarcane, pineapple, Christmas trees and other crops. Limited information exists on the metabolism of HPME in both plants and animals, haloxyfop-p has been recovered as the major metabolite in plants and in soil [5]

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