Impact of prenatal arsenic exposure on the testes and epididymides of prepubertal rats

Toxic impacts of arsenic bioaccumulation on urinary arsenic metabolites and semen quality: A systematic and meta-analysis

This study aims to investigate the effect of arsenic exposure on urinary levels of arsenic metabolites, semen parameters, and testosterone concentrations. A systematic comprehensive literature search was conducted up till 31st January 2024 using Embase, MEDLINE/Pubmed, and Scopus. This study adopted the Population Exposure Comparator Outcome and Study Design (PECOS) framework. Four studies with a total of 380 control subjects and 347 exposed men were included. Arsenic exposure significantly increased urinary levels of total arsenic (Mean Difference (MD) - 53.35 [95 % Confidence Interval (CI): - 100.14, - 6.55] P= 0.03), and reduced primary arsenic methylation index (PMI) (MD 0.22 [95 % CI: 0.14, 0.31] P< 0.00001), semen volume (MD 0.30 [95 % CI: 0.05, 0.54] P= 0.02) and total testosterone (MD 0.48 [95 % CI: 0.23, 0.73] P= 0.0002). In addition, arsenic exposure marginally reduced sperm concentration (MD 25.04 [95 % CI: - 45.42, 95.50] P= 0.49) and total sperm motility (MD 22.89 [95 % CI: - 14.15, 59.94] P= 0.23). The present meta-analysis demonstrates that arsenic exposure lowers semen quality and testosterone levels. Since the general human population is exposed to arsenic occupationally or domestically, adequate strategic measures should be put in place to limit arsenic exposure in an attempt to preserve semen quality. In addition, studies investigating interventions that may inhibit the bioaccumulation of arsenic in men who are exposed are recommended.

Subchronic intake of arsenic at environmentally relevant concentrations causes histological lesions and oxidative stress in the prostate of adult Wistar rats

The prostate gland is one of the main sites of hyperplasia and cancer in elderly men. Numerous factors have been demonstrated to disrupt prostate homeostasis, including exposure to environmental pollutants. Arsenic is a metalloid found ubiquitously in soil, air, and water, which favors human poisoning through the involuntary intake of contaminated drinking water and food and has harmful effects by increasing the oxidative stress response. This study aimed to investigate the effects of prolonged exposure to arsenic at environmentally relevant concentrations on the prostate biology of adult Wistar rats. Thirty 80-day-old male rats were divided into three experimental groups. Rats from the control group received filtered water, whereas animals from the arsenic groups ingested 1 mg L-1 and 10 mg L-1 of arsenic, in the form of sodium arsenite, daily. The arsenic solutions were provided ad libitum in the drinking water for eight weeks. Our results showed that 1 mg L-1 and 10 mg L-1 of arsenic made the prostate susceptible to evolving benign and premalignant histopathological changes. While the ingestion of 1 mg L-1 of arsenic reduced SOD activity only, 10 mg L-1 diminished SOD and CAT activity in the prostate tissue, culminating in high MDA production. These doses, however, did not affect the intraprostatic levels of DHT and estradiol. In conclusion, exposure to arsenic at environmentally relevant concentrations through drinking water induces histological and oxidative stress-related changes in the prostate of adult rats, strengthening the between arsenic exposure and prostate disorders.

Acetate Abates Arsenic-Induced Male Reproductive Toxicity by Suppressing HDAC and Uric Acid-Driven Oxido-inflammatory NFkB/iNOS/NO Response in Rats

Arsenic is associated with male reproductive toxicity through histone deacetylation and oxido-inflammatory injury. Notwithstanding, short-chain fatty acids such as acetate exert anti-oxido-inflammatory activities and inhibit histone deacetylation. This study investigated the impact of acetate on arsenic-induced male reproductive toxicity. Forty eight adult male Wistar rats were allotted into any of these four groups (n = 12 rats per group): vehicle-treated, sodium acetate-treated, arsenic-exposed, and arsenic-exposed + sodium acetate-treated. The results revealed that arsenic exposure prolonged the latencies of mount, intromission, and ejaculation and reduced the frequencies of mount, intromission, and ejaculation, as well as mating and fertility indices, litter size and weight, anogenital distance, anogenital index, and survival rate in male F1 offspring at weaning. Also, arsenic reduced the circulating levels of gonadotropin-releasing hormone, luteinizing hormone, follicle-stimulating hormone, and testosterone and testicular 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase activities. In addition, arsenic reduced the daily and total spermatid production, sperm count, motility, and viability but increased the percentage of sperm cells with abnormal morphology. Furthermore, arsenic increased testicular xanthine oxidase activity, uric acid, and malondialdehyde levels, and reduced glutathione content, superoxide dismutase and catalase activities, total antioxidant capacity, and Nrf2 level. More so, arsenic exposure increased testicular iNOS activity and nitric oxide (NO), TNF-α, IL-1β, IL-6, and NFkB levels as well as Bax, caspase 9, and caspase 3 activities, and reduced Bcl-2. These findings were associated with arsenic-induced increase in testicular arsenic concentration, histone deacetylase activity, and reduced testicular weight. Histopathological examination revealed that arsenic also disrupted testicular histoarchitecture, which was accompanied by altered testicular planimetry and reduced spermatogenic cells. Notwithstanding, sodium acetate alleviated arsenic-induced sexual dysfunction as well as biochemical and histological alterations. These were accompanied acetate-driven downregulation of histone deacetylase (HDAC) activity. Succinctly, acetate attenuated arsenic-induced male reproductive toxicity by suppressing HDAC and uric acid-driven oxido-inflammatory NFkB/iNOS/NO response.

Reproductive and Developmental Effects of Sex-Specific Chronic Exposure to Dietary Arsenic in Zebrafish (Danio rerio)

The present study investigated the reproductive and developmental effects of sex-specific chronic exposure to dietary arsenic in zebrafish. Adult zebrafish (Danio rerio) were exposed to environmentally realistic doses of arsenic via diet [0 (control; no added arsenic), 30 (low), 60 (medium), and 100 (high) μg/g dry weight, as arsenite] for 90 days. Following exposure, arsenic-exposed females from each dietary treatment were mated with control males, and similarly, arsenic-exposed males from each dietary treatment were mated with control females. In females, arsenic exposure resulted in a dose-dependent decrease in reproductive performance (fecundity, fertilization success, and hatching success). Moreover, a dose-dependent increase in developmental toxicity (larval deformities and larval mortality) was observed with maternal exposure to arsenic. In contrast, in males, arsenic exposure also induced similar reproductive and developmental toxicity; however, the adverse effects were mainly evident only in the medium and high dietary arsenic treatment groups. We also examined the sex-specific effects of dietary arsenic exposure on the expression of genes that regulate the hypothalamus-pituitary-gonadal-liver (HPG-L) axis in fish. The gene expression results indicated the downregulation of HPG-L axis genes in females irrespective of the arsenic treatment dose; however, the reduced expression of HPG-L axis genes in males was recorded only in the medium and high arsenic treatment groups. These observations suggest that chronic arsenic exposure in either females or males causes reproductive and developmental toxicity in zebrafish. However, these toxic effects are markedly higher in females than in males. Our results also suggest that arsenic can act as an endocrine disruptor and mediate reproductive and developmental toxicity by disrupting the HPG-L axis in zebrafish.

Gold nanoparticle intratesticular injections as a potential animal sterilization tool: Long-term reproductive and toxicological implications

This study aimed to evaluate the gold nanoparticles (AuNPs) animal sterilizing potential after intratesticular injections and long-term adverse reproductive and systemic effects. Adult male Wistar rats were divided into control and gold nanoparticle (AuNPs) groups. The rats received 200µL of saline or AuNPs solution (16µg/mL) on experimental days 1 and 7 (ED1 and ED7). After 150 days, the testicular blood flow was measured, and the rats were mated with females. After mating, male animals were euthanized for histological, cellular, and molecular evaluations. The female fertility indices and fetal development were also recorded. The results indicated increased blood flow in the testes of treated animals. Testes from treated rats had histological abnormalities, shorter seminiferous epithelia, and oxidative stress. Although the sperm concentration was lower in the AuNP-treated rats, there were no alterations in sperm morphology. Animals exposed to AuNPs had decreased male fertility indices, and their offspring had lighter and less efficient placentas. Additionally, the anogenital distance was longer in female fetuses. There were no changes in the histology of the kidney and liver, the lipid profile, and the serum levels of LH, testosterone, AST, ALT, ALP, albumin, and creatinine. The primary systemic effect was an increase in MDA levels in the liver and kidney, with only the liver experiencing an increase in CAT activity. In conclusion, AuNPs have a long-term impact on reproduction with very slight alterations in animal health. The development of reproductive biotechnologies that eliminate germ cells or treat local cancers can benefit from using AuNPs.

Long-term reproductive effects in male rats prenatally exposed to sodium arsenite

Arsenic is an environmental toxicant known to be a carcinogen and endocrine disruptor. Maternal exposure to arsenic has been associated with fetus malformation and reproductive disorders in male offspring. However, it is unclear the extent to which those effects remain during postnatal development and adulthood. Therefore, this study aimed to investigate the long-term effects of prenatal arsenic exposure on reproductive parameters of male offspring at peripubertal and adult periods. Pregnant female Wistar rats were exposed to 0 or 10 mg/L sodium arsenite in drinking water from gestational day 1 (GD 1) until GD 21 and male pups were analyzed at postnatal day 44 (PND 44) and PND 70. We observed that some reproductive parameters were affected differently by arsenic exposure at each age evaluated. The body and reproductive organs weights, as well as testicular and epididymal morphology were strongly affected in peripubertal animals and recovered at adult period. On the other hand, the antioxidant genes expression (SOD1, SOD2, CAT and GSTK1) and the endogenous antioxidant system were affected in the testes and epididymides from both peripubertal and adult rats. Finally, an impairment in daily sperm production and in sperm parameters was observed in adult animals. Taken together, our findings show that prenatal arsenic exposure affected reproductive parameters of peripubertal and adult male rats mainly due to oxidative stress. Collectively, those alterations may be affecting fertility potential of adult animals.

Independent and combined associations of urinary arsenic exposure and serum sex steroid hormones among 6-19-year old children and adolescents in NHANES 2013-2016

Arsenic exposure may disrupt sex steroid hormones, causing endocrine disruption. However, human evidence is limited and inconsistent, especially for children and adolescents. To evaluate the independent and combined associations between arsenic exposure and serum sex steroid hormones in children and adolescents, we conducted a cross-sectional analysis of data from 1063 participants aged 6 to 19 years from the 2013-2016 National Health and Nutrition Examination Survey (NHANES). Three urine arsenic metabolites were examined, as well as three serum sex steroid hormones, estradiol (E₂), total testosterone (TT), and sex hormone-binding globulin (SHBG). The ratio of TT to E₂ (TT/E₂) and the free androgen index (FAI) generated by TT/SHBG were also assessed. Linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to evaluate the associations of individual or arsenic metabolite combinations with sex steroid hormones by gender and age stratification. Positive associations were found between total arsenic and arsenic metabolites with TT, E₂, and FAI. In contrast, negative associations were found between arsenic metabolites and SHBG. Furthermore, there was an interaction after gender-age stratification between DMA and SHBG in female adolescents. Notably, based on the WQS and BKMR model results, the combined association of arsenic and its metabolites was positively associated with TT, E₂, and FAI and negatively associated with SHBG. Moreover, DMA and MMA dominated the highest weights among the arsenic metabolites. Overall, our results indicate that exposure to arsenic, either alone or in mixtures, may alter sex steroid hormone levels in children and adolescents.

Contemporary Comprehensive Review on Arsenic-Induced Male Reproductive Toxicity and Mechanisms of Phytonutrient Intervention

Arsenic (As) is a poisonous metalloid that is toxic to both humans and animals. Drinking water contamination has been linked to the development of cancer (skin, lung, urinary bladder, and liver), as well as other disorders such as diabetes and cardiovascular, gastrointestinal, neurological, and developmental damage. According to epidemiological studies, As contributes to male infertility, sexual dysfunction, poor sperm quality, and developmental consequences such as low birth weight, spontaneous abortion, and small for gestational age (SGA). Arsenic exposure negatively affected male reproductive systems by lowering testicular and accessory organ weights, and sperm counts, increasing sperm abnormalities and causing apoptotic cell death in Leydig and Sertoli cells, which resulted in decreased testosterone synthesis. Furthermore, during male reproductive toxicity, several molecular signalling pathways, such as apoptosis, inflammation, and autophagy are involved. Phytonutrient intervention in arsenic-induced male reproductive toxicity in various species has received a lot of attention over the years. The current review provides an in-depth summary of the available literature on arsenic-induced male toxicity, as well as therapeutic approaches and future directions.

Recent advancements in toxicology, modern technology for detection, and remedial measures for arsenic exposure: review

Arsenic toxicity has become a major global health concern for humans and animals due to extensive environmental and occupational exposure to arsenic-contaminated water, air, soil, and plant and animal origin food. It has a wide range of detrimental effects on animals, humans, and the environment. As a result, various experimental and clinical studies were undertaken and are undergoing to understand its source of exposures, pathogenesis, identify key biomarkers, the medical and economic impact on affected populations and ecosystems, and their timely detection and control measures. Despite these extensive studies, no conclusive information for the prevention and control of arsenic toxicity is available, owing to complex epidemiology and pathogenesis, including an imprecise approach and repetitive work. As a result, there is a need for literature that focuses on recent studies on the epidemiology, pathogenesis, detection, and ameliorative measures of arsenic toxicity to assist researchers and policymakers in the practical future planning of research and community control programs. According to the preceding viewpoint, this review article provides an extensive analysis of the recent progress on arsenic exposure to humans through the environment, livestock, and fish, arsenic toxicopathology, nano-biotechnology-based detection, and current remedial measures for the benefit of researchers, academicians, and policymakers in controlling arsenic eco-toxicology and directing future research. Arsenic epidemiology should therefore place the greatest emphasis on the prevalence of different direct and indirect sources in the afflicted areas, followed by control strategies.

Effect of heavy metals on epididymal morphology and function: An integrative review

Male fertility has deteriorated over the last decades, and environmental risk factors are among the possible causes of this phenomenon. Pollutants such as heavy metals might accumulate in male reproductive organs to levels that are associated with reproductive disorders. Several studies reported detrimental effects of inorganic arsenic (iAs⁺³/iAs⁺⁵), cadmium (Cd⁺²), lead (Pb⁺²), and mercury (Hg⁺²/CH₃Hg⁺²) on the epididymis, which plays a crucial role in sperm maturation. However, the magnitude of their effects and the consequences on the physiology of the epididymis are still unclear. Therefore, an integrative review with meta-analyses was conducted examining 138 studies to determine how exposure to arsenic, cadmium, lead, and mercury affects epididymal morphology and functions, using primarily murine data from experimental studies as a source. This study showed that exposure to metal(loids) reduced epididymal weight, sperm motility, and sperm number. Inorganic arsenic, cadmium, and lead damaged sperm structures within the epididymal duct. While sodium arsenite, sodium arsenate, and lead acetate generate oxidative stress by an imbalance between ROS production and scavenging, cadmium chloride causes an increase in the pH level of the luminal fluid (from 6.5 to 7.37) that diminishes sperm viability. Inorganic arsenic induced a delay in the sperm transit time by modulating noradrenaline and dopamine secretion. Subacute exposure to heavy metals at concentrations < 0.1 mg L^-1 initiates a dyshomeostasis of calcium, copper, iron, and zinc that disturbs sperm parameters and reduces epididymal weight. These alterations worsen with prolonged exposure time and higher doses. Most studies evaluated the effects of concentrations > 1.1 mg L^-1 of heavy metals on the epididymis rather than doses with relevant importance for human health risk. This meta-analytical study faced limitations regarding a deeper analysis of epididymis physiology. Hence, several recommendations for future investigations are provided. This review creates a baseline for the comprehension of epididymal toxicology.

Glutathione S-transferase kappa 1 is positively related with sperm quality of porcine sperm

The glutathione S-transferase (GST) superfamily members play an important role in the male reproductive tract and sperm physiology. However, the expression profiles of some members of this protein family and their effect on sperm quality remain unclear. In this study, we found that GST kappa 1 (GSTK1) encoded protein is abundant in the testes and capacitated sperm acrosome. Western blot analysis revealed that the decreased abundance of GSTK1 was observed in low motile spermatozoa; moreover, GSTK1 expression decreased in sperm stored at 17°C under a long preservation time. In vitro analyses revealed that GSTK1 had no significant effect on sperm motility, capacitation, or acrosome reaction. Notably, after capacitated sperm were incubated with 4 and 8 μg/ml anti-GSTK1 antibodies, the fertilization rate significantly decreased in vitro fertilization assay. The current study demonstrates that GSTK1 is correlated with sperm quality and is a promising marker for the assessment of sperm quality and provides a basis for understanding the potential molecular mechanism for targeting pathogenic factors in male infertility.

Molecular perspective concerning fluoride and arsenic mediated disorders on epididymal maturation of spermatozoa: A concise review

Epididymis is a complex tubular structure of male reproductive system where spermatozoa undergo maturation and gain the fertilizing ability. Epididymal pseudostratified columnar epithelium with different cell types play imperative role by their secretory properties and enrich the luminal microenvironment necessary for achieving spermatozoal motility. During epididymal transit several secretory proteins like P26h, SPAG11, HSPD1 and many others are deposited on spermatozoal surface. At the same time spermatozoal proteins are also modified in this intraluminal milieu, which include cyritestin, fertilin, CE9 and others. Natural and anthropogenic activities disclose various environmental pollutants which affect different physiological systems of animals and human being. Likewise, reproductive system is also being affected. Fluoride causes structural alterations of caput and cauda segments of epididymis. Redox homeostasis and functional integrity are also altered due to diminished activities of SOD1, GR, Crisp2, Lrp2 and other important proteins. On the contrary arsenic affects mostly on cauda segment. Redox imbalance and functional amendment in epididymis have been observed with arsenic revelation as evidenced by altered genomic appearance of SOD, GST, catalase, Ddx3Y, VEGF and VEGFR2. This review is dealt with structure-function interplay in normal epididymal spermatozoal maturation along with subsequent complications developed under fluoride and arsenic toxicities.