TITLE:
Genomic Instability Is a Mechanism for Diminished Male Fertility Following Chronic Dichlorvos Exposure
AUTHORS:
Raymond A. Vhriterhire, Samuel O. Odeh, Gideon U. Egesie
KEYWORDS:
Genomic Instability, Micronuclei, Male Infertility, Dichlorvos, Chronic Organophosphate Exposure
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.11 No.7,
July
11,
2023
ABSTRACT: Background and Objectives: Chronic low-dose exposure to dichlorvos occurs in communities in Africa where the substance is used indiscriminately for a variety of purposes. This experiment used an animal model to evaluate genomic instability induced by this pattern of chronic exposure and its relationship with some measures of fertility in males. Methods: Seventy-five male Rattus norvegicus rats obtained for this experiment, were randomly allotted into five groups. Dichlorvos was given by oral gavage at doses of 0.28 mg/kg, 0.56 mg/kg and, 1.68 mg/kg, respectively, to three of the groups, on alternate days for 50 weeks. The remaining two groups received plain drinking water and cyclophosphamide as negative and positive controls, respectively. Samples were collected at 17, 34, and 50 weeks. Sperm count, sperm morphology and serum levels of follicle-stimulating hormone, luteinizing hormone, dihydrotestosterone, oestrogen and progesterone were determined. Furthermore, the frequency of micronucleated polychromatic erythrocytes was determined in bone marrow cells obtained from the femur. Results: The mean ranks of micronuclei frequency had an increasing trend. The frequency of micronucleated polychromatic erythrocytes (MnPCE) had a significant negative correlation with oestrogen (rs = -0.47, p = 0.00, n = 50), follicle-stimulating hormone (rs = -0.41, p = 0.00, n = 50) and progesterone (rs = -0.37, p = 0.01, n = 50) serum levels. A positive monotonic relationship also existed between micronuclei frequency and those of tubular necrosis, tubular vacuolation, and residual bodies. A positive significant moderate correlation was found between MnPCE and the proportion of immotile sperms (rs = 0.41, p = 0.00, n = 50). Conclusion: The nature of the correlations between micronuclei frequency and the proportion of immotile sperms, adverse histological changes and serum hormone levels found in this study suggest genomic instability as the possible mechanism for diminished fertility in males chronically exposed to dichlorvos.