60-Day Chronic Exposure to Low Concentrations of HgCl2 Impairs Sperm Quality: Hormonal Imbalance and Oxidative Stress as Potential Routes for Reproductive Dysfunction in Rats

Abstract

Mercury is a toxic and bio-accumulative heavy metal of global concern. While good deals of research have been conducted on the toxic effects of mercury, little is known about the mechanisms involved in the pathogenesis of male reproductive dysfunction induced by mercury. Therefore, the purpose of this study was to assess the effects and underlying mechanisms of chronic mercury exposure at low levels on male reproductive system of rats. Three-month-old male Wistar rats were divided into two groups and treated for 60 days with saline (i.m., Control) and HgCl2 (i.m. 1st dose: 4.6 µg/kg, subsequent doses 0.07 µg/kg/day). We analyzed sperm parameters, hormonal levels and biomarkers of oxidative stress in testis, epididymis, prostate and vas deferens. Mercury treatment decreased daily sperm production, count and motility and increased head and tail morphologic abnormalities. Moreover, mercury treatment decreased luteinizing hormone levels, increased lipid peroxidation on testis and decreased antioxidant enzymes activities (superoxide dismutase and catalase) on reproductive organs. Our data demonstrate that 60-day chronic exposure to low concentrations of HgCl2 impairs sperm quality and promotes hormonal imbalance. The raised oxidative stress seems to be a potential mechanism involved on male reproductive toxicity by mercury.

Oral administration ofMoringa oleiferaoil but not coconut oil prevents mercury-induced testicular toxicity in rats

“…The most important route of human exposure is the ingestion of fish, seafood (methyl‐Hg) as well as foods of plant origin. However, human exposure can also occur through dental amalgam fillings (metallic‐Hg), pharmaceuticals such as vaccines (ethyl‐Hg), drinking of contaminated water, as well as inhalation of air containing HgCl 2 (Nyland et al ., ; Martinez et al ., ).…”

“…Several studies in different experimental models have reported the male reproductive toxicity of Hg (Ghaffari & Motlagh, ; Martinez et al ., ). For example, Hg compounds are known to affect testicular spermatogenic and steroidogenic functions in experimental animals (Fossato da Silva et al ., ; El‐Desoky et al ., ), decrease the reproductive performance of mice (Khan et al ., ), affect germ cell development, promote germ cell injury (El‐Desoky et al ., ), alter reproductive behaviour (Khan et al ., ), decrease sperm count, morphology and motility in monkeys and rodents (Boujbiha et al ., ; El‐Desoky et al ., ), induce androgen deficiency in experimental animals and consequently impair accessory sex glands (El‐Desoky et al ., ).…”

“…reduced glutathione) necessary for cellular protection against reactive oxygen species (e.g. H 2 O 2 ) and increased levels of malondialdehyde have all been reported in the literature (Perottoni et al ., ; Martinez et al ., ).…”

Mercury Biodistribution in Rats after Chronic Exposure to Mercury Chloride

“…According to the works of Martinez et al, [45][46][47] intramuscular injections of mercury chloride for 30 and 60 days in a low-dose regimen induced reproductive dysfunction characterized by impaired sperm quality, hormonal dysfunction and associated with increased oxidative stress on male reproductive system of rats. Studies in mice treated using oral administration of mercury chloride also evidenced a dose-dependent adverse effects on male rat reproduction endpoints including infertility and, in female rats, disruption of implantation of the ovum into the uterus and fetal viability.…”

Citalopram Induces Reproductive Toxicity in Male Rats

“…A total of 200 sperms/animal were analyzed. The morphometric parameters of head and tail were determined, and abnormal sperms were detected based on previous criteria (Mori et al, ; Filler, ; Narayana et al, ; Gromadzka‐Ostrowska et al, ; Martinez et al, ). Sperms with banana‐shaped head, amorphous head, bent neck, or two‐headed and headless sperms were considered as having head abnormalities, whereas sperms with a bent or broken tail were considered as having tail abnormalities (Fig.…”