Oxidative damage of the male reproductive system induced by paraquat

Sudachitin Alleviates Paraquat Instigated Testicular Toxicity in Albino Rats via Regulating Nrf-2/Keap-1, Inflammatory, Steroidogenic, and Histological Profile

Paraquat (PQ) is a noxious herbicide which adversely affects the vital organs including male reproductive system. Sudachitin (SCN) is a naturally occurring flavonoid that demonstrates a wide range of biological potentials. The current study was designed to investigate the alleviative potential of SCN to avert PQ-induced testicular toxicity in rats. Forty-eight male rats (Rattus norvegicus) were apportioned into four groups including control, PQ (5 mg/kg), PQ + SCN (5 mg/kg + 30 mg/kg), and SCN (30 mg/kg) only treated group. Our findings elucidated that PQ treatment reduced the expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and its antioxidant genes as well as the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GSR) and glutathione peroxidase (GPx), while elevating the levels of reactive oxygen species (ROS), and malondialdehyde (MDA). Furthermore, PQ intoxication upregulated the expressions of Keap-1 while downregulating the expression of 3-beta hydroxysteroid dehydrogenase (3β-HSD), 17-beta hydroxysteroid dehydrogenase (17β-HSD), and steroidogenic acute regulatory protein (StAR). Moreover, sperm anomalies were increased following the exposure to PQ. Besides, PQ exposure decreased the levels of plasma testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) while increasing the levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), nuclear factor-kappa B (NF-κB), interleukin-1beta (IL-1β), and cyclooxygenase-2 (COX-2). Additionally, PQ treatment escalated the expressions of cysteinyl aspartate-specific proteases-3 (Caspase-3) and Bcl-2-associated X-protein (Bax) while downregulating the expressions of B-cell lymphoma-2 (Bcl-2). Furthermore, PQ exposure disrupted the normal architecture of testicular tissues. However, SCN treatment remarkably protected the testicular tissues via regulating the aforementioned disruptions owing to its antioxidant, anti-inflammatory, and androgenic potential.

Diquat causes mouse testis injury through inducing heme oxygenase-1-mediated ferroptosis in spermatogonia

Diquat dibromide (DQ) is a globally used herbicide in agriculture, and its overuse poses an important public health issue, including male reproductive toxicity in mammals. However, the effects and molecular mechanisms of DQ on testes are limited. In vivo experiments, mice were intraperitoneally injected with 8 or 10 mg/kg/ day of DQ for 28 days. It has been found that heme oxygenase-1 (HO-1) mediates DQ-induced ferroptosis in mouse spermatogonia, thereby damaging testicular development and spermatogenesis. Histopathologically, we found that DQ exposure caused seminiferous tubule disorders, reduced germ cells, and increased sperm malformation, in mice. Reactive oxygen species (ROS) staining of frozen section and transmission electron microscopy (TEM) displayed DQ promoted ROS generation and mitochondrial morphology alterations in mouse testes, suggesting that DQ treatment induced testicular oxidative stress. Subsequent RNA-sequencing further showed that DQ treatment might trigger ferroptosis pathway, attributed to disturbed glutathione metabolism and iron homeostasis in spermatogonia cells in vitro. Consistently, results of western blotting, measurements of MDA and ferrous iron, and ROS staining confirmed that DQ increased oxidative stress and lipid peroxidation, and accelerated ferrous iron accumulation both in vitro and in vivo. Moreover, inhibition of ferroptosis by deferoxamine (DFO) markedly ameliorated DQ-induced cell death and dysfunction. By RNA-sequencing, we found that the expression of HO-1 was significantly upregulated in DQ-treated spermatogonia, while ZnPP (a specific inhibitor of HO-1) blocked spermatogonia ferroptosis by balancing intracellular iron homeostasis. In mice, administration of the ferroptosis inhibitor ferrostatin-1 effectively restored the increase of HO-1 levels in the spermatogonia, prevented spermatogonia death, and alleviated the spermatogenesis disorders induced by DQ. Overall, these findings suggest that HO-1 mediates DQ-induced spermatogonia ferroptosis in mouse testes, and targeting HO-1 may be an effective protective strategy against male reproductive disorders induced by pesticides in agriculture.

Curative effects of tectochrysin on paraquat-instigated testicular toxicity in rats: A biochemical and histopathological based study

Background

Paraquat (PQ) is a herbicide that is used globally in the agriculture sector to eradicate unwanted weeds, however it also induces significant damages in various organs of the body such as testes. Tectochrysin (TEC) is an important flavonoid that shows versatile therapeutic potentials. Currently, there is no established antidote to cure PQ-induced testicular toxicity.

Objective

The present study was conducted to evaluate the ameliorative effects of TEC against PQ prompted testicular damage.

Methods

Sprague-Dawley rats (n = 48) were used to conduct the trial. Rats were allocated in to 4 groups i.e., Control, PQ administrated group (5 mgkg-1), PQ + TEC co-administrated group (5 mgkg-1 + 2.5 mgkg-1) and TEC only administrated group (2.5 mgkg-1). The trial was conducted for 8 weeks. The activity of anti-oxidants and the levels of MDA and ROS were determined by spectrophotometric method. Steroidogenic enzymes as well as apoptotic markers expressions were evaluated by qRT-PCR. The level of hormones and inflammatory indices was quantified by enzyme-linked immunosorbent assay.

Results

PQ exposure markedly (P < 0.05) disturbed the biochemical, spermatogenic and histological profile in the rats. Nevertheless, TEC treatment considerably (P < 0.05) increased CAT, GPx GSR and SOD activity, besides decreasing MDA and ROS contents. TEC administration also increased sperm viability, count and motility. 17β-HSD, 3β-HSD, StAR and Bcl-2 expressions were also increased following TEC administration. The supplementation of TEC substantially (P < 0.05) decreased Bax, Caspase-3 expression and the levels of inflammatory markers i.e., interleukin-1β (IL-1β), interleukin-6 (IL-6), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) activity. Additionally, the levels of plasma testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were increased following TEC supplementation. Furthermore, TEC supplementation considerably decreased sperm structural abnormalities and histomorphological damages of the testes. The mitigative role of TEC might be due to its anti-inflammatory, anti-apoptotic, androgenic and anti-oxidant potentials.

Conclusion

Taken together, it is concluded that TEC can be used as a potential candidate to treat testicular toxicity.

Assessing the impact and mechanisms of environmental pollutants (heavy metals and pesticides) on the male reproductive system: a comprehensive review

The escalation of technological advancements, coupled with the increased use of hazardous chemicals, has emerged as a significant concern for human health. Exposure to environmental pollutants like heavy metals and pesticides (insecticides, herbicides and fungicides) is known to significantly contribute to various health problems, particularly affecting reproductive health. Disturbances in reproductive potential and reproductive toxicity in males are particularly worrisome. Existing literature suggests that exposure to these environmental pollutants significantly alters male reproductive parameters. Thus, it is imperative to thoroughly analyze, comprehend, and evaluate their impact on male reproductive toxicity. Oxidative stress and disruptions in redox equilibrium are major factors through which these pollutants induce changes in sperm parameters and affect the reproductive system. Insecticides, fungicides, and herbicides act as endocrine disruptors, interfering with the secretion and function of reproductive hormones such as testosterone and luteinizing hormone (LH), consequently impacting spermatogenesis. Additionally, heavy metals are reported to bio-accumulate in reproductive organs, acting as endocrine disruptors and triggering oxidative stress. The co-operative association of these pollutants can lead to severe damage. In this comprehensive review, we have conducted an in-depth analysis of the impact of these environmental pollutants on the male reproductive system, shedding light on the underlying mechanisms of action.

Sciadopitysin mitigates spermatological and testicular damage instigated by paraquat administration in male albino rats

Paraquat (PQ) is a herbicide that has ability to induce testicular toxicity by producing reactive oxygen species (ROS). Sciadopitysin (SPS) is a promising flavonoid that displays multiple pharmacological properties i.e., anti-inflammatory, anti-oxidant and anti-apoptotic. Therefore, the present study was designed to evaluate the mitigative role of SPS against PQ induced testicular toxicity in male rats. The experiment was performed on male albino rats (n = 48) that were divided into 4 groups. The group-1 was control group. Group-2 was administrated orally with PQ (5 mg/kg). Group-3 was administrated orally with PQ (5 mg/kg) and SPS (2 mg/kg). Group-4 was supplemented with SPS (2 mg/kg) through oral gavage. The experiment was conducted for 56 days. The exposure to PQ significantly lowered the activities of catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD) as well as glutathione peroxidase (GPx). Whereas, a substantial increase was observed in dead sperms number, abnormalities in the tail, head as well as midpiece of sperms in PQ intoxicated rats. Moreover, a significant increase in the level of ROS and malondialdehyde (MDA) was noticed in PQ administrated group. Furthermore, steroidogenic enzymes expression was significantly decreased in PQ-intoxicated group, whereas the level of inflammatory markers was increased in PQ administrated rats. Besides, the expression of apoptotic markers was significantly escalated in PQ exposed rats, whereas the expression of anti-apoptotic markers was considerably reduced. A significant reduction in hormonal level was also noticed in the rats that were administrated with PQ. Moreover, the histopathological examination revealed that PQ significantly damaged the testicles. However, the supplementation of SPS with PQ significantly reduced the adverse effects of PQ in the testes of albino rats. Therefore, the current investigation demonstrated that SPS possesses a significant potential to avert PQ-induced testicular dysfunction due to its anti-apoptotic, androgenic, anti-oxidant and anti-inflammatory nature.

Exposure to 4-nonylphenol compromises Leydig cell development in pubertal male mice

Exposure to 4-nonyl phenol (4-NP) on Leydig cell (LC) development and function remains poorly understood. We explored the effects of 4-NP on LC development and elucidate the underlying mechanisms. Male (28-day-old) mice received orally 4-NP (0.125, 0.25, and 0.5 mg/kg/day) for 28 days. We found that 4-NP at ≥ 0.125 mg/kg markedly compromised serum testosterone levels and LC numbers. Gene and protein expression analysis demonstrated downregulation of key genes and their proteins involved in LC steroidogenesis, including Star, Cyp11a1, Cyp17a1, Hsd17b3, Hsd3b6, and Scarb1. Furthermore, exposure to 4-NP induced oxidative stress, as evidenced by elevated reactive oxygen species (ROS) and malondialdehyde (MDA), as well as reduced superoxide dismutase 1/2 and catalase (CAT). Apoptosis was also observed in LCs following exposure to 4-NP, as shown by an increased BAX/BCL2 ratio and caspase-3. A TM3 mouse LC line further confirmed that 4-NP induced ROS and the expression of apoptosis-related genes and proteins. In conclusion, this study demonstrates that 4-NP exposure compromises LC development through multiple mechanisms.

Exposure to bromoxynil octanoate herbicide induces oxidative stress, inflammation, and apoptosis in testicular tissue via modulating NF-кB pathway

Bromoxynil octanoate (BO) is a herbicide necessary for plant growth and production. However, it may cause damage to environment and humans. This study aimed to investigate the potential testicular toxicity of BO and its possible underlying mechanisms. Male Albino (Sprague Dawley) rats were administered BO in different doses (5, 10, 20, and 40 mg/kg/BW; P.O.) daily for 21 days. Testicular function was evaluated by determining count and viability of epididymal sperm, and testosterone. In addition, the following parameters were assessed; MDA, NO, and H2O2 as oxidative stress markers; SOD, CAT, GPx, GST, and GSH as antioxidant markers; NF-ĸB-P65 and IL-18 as inflammatory markers; caspase-9 and caspase-3 as apoptotic markers; gene expression of NF-ĸB-P65, TNF-α, BAX, Bcl-2, and caspase-3; and histopathological examination of epididymis and testis sections. The results showed a significant (P < 0.05) increase in MDA, NO, H2O2, IL-18, and caspase-9 content, NF-ĸB-P65, TNF-α, Bax, and Caspase-3 expression as compared to control. Furthermore, the count and viability of epididymal sperm, testosterone level, SOD, CAT, GPx, GST, and GSH content, and Bcl-2 expression showed a significant (P < 0.05) decrease as compared to control. In conclusion BO-induced testicular damage by altering oxidation, inflammation, and apoptosis.

Putative adverse outcome pathways of the male reproductive toxicity derived from toxicological studies of perfluoroalkyl acids

Adverse outcome pathway (AOP) as a conceptual framework is a powerful tool in the field of toxicology to connect seemingly discrete events at different levels of biological organizations into an organized pathway from molecular interactions to whole organism toxicity. Based on numerous toxicological studies, eight AOPs for reproductive toxicity have been endorsed by the Organization for Economic Co-operation and Development (OECD) Task Force on Hazard Assessment. We have conducted a literature survey on the mechanistic studies on male reproductive toxicity of perfluoroalkyl acids (PFAAs), a class of global environmental contaminants with high persistence, bioaccumulation and toxicity. Using the AOP development strategy, five new AOPs for male reproductive toxicity were proposed here, namely (1) changes in membrane permeability leading to reduced sperm motility, (2) disruption of mitochondrial function leading to sperm apoptosis, (3) decreased gonadotropin-releasing hormone (GnRH) expression in hypothalamus leading to reduced testosterone production in male rats, (4) activation of the p38 signaling pathway leading to disruption of BTB in mice, (5) inhibition of p-FAK-Tyr407 activity leading to the destruction of BTB. The molecular initiating events in the proposed AOPs are different from those in the endorsed AOPs, which are either receptor activation or enzyme inhibition. Although some of the AOPs are still incomplete, they can serve as a building block upon which full AOPs can be developed and applied to not only PFAAs but also other chemical toxicants with male reproductive toxicity.

An Adverse Outcome Pathway Network for Chemically Induced Oxidative Stress Leading to (Non)genotoxic Carcinogenesis

Nongenotoxic (NGTX) carcinogens induce cancer via other mechanisms than direct DNA damage. A recognized mode of action for NGTX carcinogens is induction of oxidative stress, a state in which the amount of oxidants in a cell exceeds its antioxidant capacity, leading to regenerative proliferation. Currently, carcinogenicity assessment of environmental chemicals primarily relies on genetic toxicity end points. Since NGTX carcinogens lack genotoxic potential, these chemicals may remain undetected in such evaluations. To enhance the predictivity of test strategies for carcinogenicity assessment, a shift toward mechanism-based approaches is required. Here, we present an adverse outcome pathway (AOP) network for chemically induced oxidative stress leading to (NGTX) carcinogenesis. To develop this AOP network, we first investigated the role of oxidative stress in the various cancer hallmarks. Next, possible mechanisms for chemical induction of oxidative stress and the biological effects of oxidative damage to macromolecules were considered. This resulted in an AOP network, of which associated uncertainties were explored. Ultimately, development of AOP networks relevant for carcinogenesis in humans will aid the transition to a mechanism-based, human relevant carcinogenicity assessment that involves a substantially lower number of laboratory animals.

Melatonin Ameliorates Diquat-Induced Testicular Toxicity via Reducing Oxidative Stress, Inhibiting Apoptosis, and Maintaining the Integrity of Blood-Testis Barrier in Mice

Diquat is a fast, potent, and widely used bipyridine herbicide in agriculture and it induces oxidative stress in several animal models. However, its genotoxic effects on the male reproductive system remain unclear. Melatonin is an effective free-radical scavenger, which has antioxidant and anti-apoptotic properties and can protect the testes against oxidative damage. This study aimed to investigate the therapeutic effects of melatonin on diquat-induced testicular injury in mice. The results showed melatonin treatment alleviated diquat-induced testicular injury, including inhibited spermatogenesis, increased sperm malformations, declined testosterone level and decreased fertility. Specifically, melatonin therapy countered diquat-induced oxidative stress by increasing production of the antioxidant enzymes GPX1 and SOD1. Melatonin treatment also attenuated diquat-induced spermatogonia apoptosis in vivo and in vitro by modulating the expression of apoptosis-related proteins, including P53, Cleaved-Caspase3, and Bax/Bcl2. Moreover, melatonin restored the blood-testicular barrier by promoting the expression of Sertoli cell junction proteins and maintaining the ordered distribution of ZO-1. These findings indicate that melatonin protects the testes against diquat-induced damage by reducing oxidative stress, inhibiting apoptosis, and maintaining the integrity of the blood-testis barrier in mice. This study provides a theoretical basis for further research to protect male reproductive health from agricultural pesticides.

Effect of paraquat on cytotoxicity involved in oxidative stress and inflammatory reaction: A review of mechanisms and ecological implications

Paraquat (PQ) is a cheap and an effective herbicide, which is widely being used worldwide to remove weeds in cultivated crop fields. However, it can cause soil and water pollution, and pose serious harm to the environment and organisms. Several countries have started to limit or prohibit the use of PQ because of the increasing number of human deaths. Its toxicity can damage the organisms with a multi-target mechanism, which has not been fully understood yet. That is why it is hard to treat as well. The current research on PQ focuses on its targeted organ, the lungs, in which PQ mostly trigger pulmonary fibrosis. While there is a lack of systematic research, there are few studies published discussing its toxic effects at systematic level. This review summarizes the major damages caused by PQ in different organisms and partial mechanisms by which it causes these damages. For this purpose, we consulted several research articles that studied the toxicity of PQ in various tissues. We also listed some drugs that can be used to alleviate the toxicity of PQ. However, at present, the effectiveness of these drugs is still being explored in animal experiments and the study of their mechanism will also help in understanding the poisoning mechanism of PQ, which will ultimately lead to effective treatment in future.

Mechanisms of deleterious effects of some pesticide exposure on pigs

The increase in the size of the global population increases the food and energy demand, making the use of pesticides in agricultural and livestock industries unavoidable. Exposure to pesticides can be toxic to the non-target species, such as humans, wildlife, and livestock, in addition to the target organisms. Various chemicals are used in the livestock industry to control harmful organisms, such as insects, weeds, and parasites. Pigs are one of the most important food sources for humans. In addition, pigs can be used as promising models for assessing the risk of absorption of environmental pollutants through the skin and oral exposure since they are physiologically similar to humans. Exposure to numerous environmental pollutants, such as mycotoxins, persistent organic pollutants, and heavy metals, has been reported to adversely affect growth, fertility, and endocrine homeostasis in pigs. Various pesticides have been observed in porcine tissues, blood, urine, and processed foods; however, there is a lack of comprehensive understanding of their effects on porcine health. This review provides a comprehensive description of the characteristics of pesticides that pigs can be exposed to and how their exposure affects porcine reproductive function, intestinal health, and endocrine homeostasis in vivo and in vitro.

Paraquat exposure delays late-stage Leydig cell differentiation in rats during puberty

Paraquat is a fast and non-selective herbicide that is widely used in crop cultivation and conservation tillage systems. Animal experiments have shown that paraquat decreases sperm quality and testicular organ coefficient, but its effects on the development of Leydig cells remain unclear. The objective of the current study was to investigate the effects of paraquat exposure on the Leydig cell development in rats during puberty. Twenty-eight male 35-day-old Sprague-Dawley rats were divided into 4 groups: 0, 0.5, 2.0, and 8 mg kg^-1 d^-1 paraquat. Paraquat was gavaged for 10 d. Adult Leydig cells were isolated and treated with paraquat for 24 h. Paraquat in vivo significantly decreased body and testis weights at 8 mg kg^-1 and lowered serum testosterone levels at 2 and 8 mg kg^-1 without affecting the levels of serum luteinizing hormone and follicle-stimulating hormone. Paraquat did not alter Leydig cell number and PCNA labeling index. Real-time PCR showed that paraquat down-regulated the expression of Lhcgr, Scarb1, Cyp11a1, Cyp17a1, and Hsd17b3 genes and their proteins at 2 or 8 mg kg^-1, while it up-regulated the expression of Srd5a1 at 8 mg kg^-1. Paraquat increased ROS and decreased testosterone production by Leydig cells at 1 and 10 μM after in vitro 24-h exposure. Vitamin E (40 μg/ml) reversed paraquat-induced ROS and suppression of testosterone synthesis in vitro. In conclusion, paraquat directly delays Leydig cell differentiation to block testosterone synthesis via down-regulating the expression of critical testosterone synthesis-related genes and up-regulating the expression of testosterone metabolic enzyme (Srd5a1) gene and possibly via increasing ROS production.