Effects of chlorocholine chloride on pubertal development and reproductive functions in male rats

Chlormequat chloride induces hepatic steatosis by promoting mTOR/SREBP1 mediated lipogenesis via AMPK inhibition

Chlormequat chloride (CCC), a widely used plant growth regulator, is a choline analogue that has been shown to have endocrine-disrupting effects. Previous studies have shown that maternal exposure to CCC could induce hyperlipidemia and growth disruption in rat offspring. This study aims to further investigate the effects of peripubertal exposure to CCC on pubertal development and lipid homeostasis, as well as the underlying mechanisms. In vivo, male weanling rats were exposed to CCC (0, 20, 75 and 200 mg/kg bw/day) from post-natal day 21-60 via daily oral gavage. The results in rats showed that 75 mg/kg CCC treatment induced hepatic steatosis, predominantly microvesicular steatosis with a small amount of macrovesicular steatosis, in rat livers and 200 mg/kg CCC treatment induced liver damage including inflammatory infiltration, hepatic sinusoidal dilation and necrosis. In vitro, HepG2 cells were treated with CCC (0, 30, 60, 120, 240 and 480 μg/mL) for 24 h. And the results showed that CCC above 120 μg/mL induced an increase in triglyceride and neutral lipid levels of HepG2 cells. Mechanism exploration revealed that CCC treatment promoted the activation of mTOR/SREBP1 signalling pathway and inhibited activation of AMPK in both in vivo rat livers and in vitro HepG2 cells. Treatment with AMPK activator Acadesine (AICAR) could alleviate the lipid accumulation in HepG2 cells induced by CCC. Collectively, the present results indicate that CCC might induce hepatic steatosis by promoting mTOR/SREBP1 mediated lipogenesis via AMPK inhibition.

Recent advances in phyto-combined remediation of heavy metal pollution in soil

The global industrialization and modernization have witnessed a rapid progress made in agricultural production, along with the issue of soil heavy metal (HM) pollution, which has posed severe threats to soil quality, crop yield, and human health. Phytoremediation, as an alternative to physical and chemical methods, offers a more cost-effective, eco-friendly, and aesthetically appealing means for in-situ remediation. Despite its advantages, traditional phytoremediation faces challenges, including variable soil physicochemical properties, the bioavailability of HMs, and the slow growth and limited biomass of plants used for remediation. This study presents a critical overview of the predominant plant-based HM remediation strategies. It expounds upon the mechanisms of plant absorption, translocation, accumulation, and detoxification of HMs. Moreover, the advancements and practical applications of phyto-combined remediation strategies, such as the addition of exogenous substances, genetic modification of plants, enhancement by rhizosphere microorganisms, and intensification of agricultural technologies, are synthesized. In addition, this paper also emphasizes the economic and practical feasibility of some strategies, proposing solutions to extant challenges in traditional phytoremediation. It advocates for the development of cost-effective, minimally polluting, and biocompatible exogenous substances, along with the careful selection and application of hyperaccumulating plants. We further delineate specific future research avenues, such as refining genetic engineering techniques to avoid adverse impacts on plant growth and the ecosystem, and tailoring phyto-combined strategies to diverse soil types and HM pollutants. These proposed directions aim to enhance the practical application of phytoremediation and its integration into a broader remediation framework, thereby addressing the urgent need for sustainable soil decontamination and protection of ecological and human health.

Chlorocholine chloride exposure induced spermatogenic dysfunction via iron overload caused by AhR/PERK axis-dependent ferritinophagy activation

Chlorocholine chloride (CCC) is a plant growth regulator used worldwide that is detectable in cereals, fruits and animal products. The health effects of CCC exposure have raised public concern. Our previous research showed that CCC exposure decreased testosterone synthesis in pubertal rats. However, little is known about whether and how pubertal CCC exposure impacts spermatogenesis. In this study, we used BALB/c mice and spermatogonia-derived GC-1 cells to examine CCC-induced spermatogenic dysfunction. In vivo, pubertal CCC exposure led to decreased testicular weight, decreased testicular germ cells and poor sperm quality. This effect worsened after cessation of CCC exposure for the next 30 days. RNA-seq and western blot analysis revealed that CCC induced aryl hydrocarbon receptor (AhR) signaling, endoplasmic reticulum stress (ERS) and ferritinophagy. Increased iron content and lipid peroxidation levels were also observed in CCC-treated testes. In vitro, it was identified that iron overload mediated by enhanced ferritinophagy occurred in CCC-treated GC-1 cells, which might be attributed to the PERK pathway in ERS. Further, for the first time, our study elucidated the involvement of AhR in CCC-induced iron overload, which aggravated testicular oxidative damage via lipid peroxidation. Considering the adverse impact of CCC exposure on rodents, supportive evidence from GC-1 cells, and the critical importance of spermatogenesis on male development, the effects of CCC on the male reproduction warrant increased attention.

Chlormequat chloride induced activation of calmodulin mediated PI3K/AKT signaling pathway led to impaired sperm quality in pubertal mice

Chlormequat chloride (CCC), as a widely used plant growth regulator, can cause impaired sperm quality and decreased testosterone synthesis in pubertal rats, but the underlying mechanism remains unclear. The purpose of this study was to elucidate the toxicokinetics and tissue distribution of CCC, as well as the possible mechanism of CCC-induced impairment in sperm quality. The concentration of CCC reached its peak 1 h after a single dose (200 mg/kg·bw) administration in mice plasma, and a bimodal phenomenon appeared in the testes, liver, and epididymis. In vivo, 200 mg/kg CCC caused testicular damage and impaired sperm quality in pubertal mice, and the expression of p-tyrosine and GSK3α decreased in cauda epididymidis, sperm and testes. CCC also caused the down-regulation of AKAP4 and the up-regulation of calmodulin (CaM), and activated the PI3K/AKT signaling pathway in the testes. In vitro, CCC reduced the levels of p-tyrosine, AKAP4 and GSK3α, increased the level of CaM and activated the PI3K/AKT signaling pathway in GC-1 cells. CaM antagonist (W-7 hydrochloride) and PI3K inhibitor (LY294002) can effectively improve the expression of GSK3α and AKAP4 by suppressing the PI3K/AKT signaling pathway in GC-1 cells treated with CCC. It was indicated that CCC induced impairment in sperm quality might be partially related to the activation of PI3K/AKT signaling pathway mediated by CaM.

A pilot study of chlormequat in food and urine from adults in the United States from 2017 to 2023

Chlormequat chloride is a plant growth regulator whose use on grain crops is on the rise in North America. Toxicological studies suggest that exposure to chlormequat can reduce fertility and harm the developing fetus at doses lower than those used by regulatory agencies to set allowable daily intake levels. Here we report, the presence of chlormequat in urine samples collected from people in the U.S., with detection frequencies of 69%, 74%, and 90% for samples collected in 2017, 2018-2022, and 2023, respectively. Chlormequat was detected at low concentrations in samples from 2017 through 2022, with a significant increase in concentrations for samples from 2023. We also observed high detection frequencies of chlormequat in oat-based foods. These findings and chlormequat toxicity data raise concerns about current exposure levels, and warrant more expansive toxicity testing, food monitoring, and epidemiological studies to assess health effects of chlormequat exposures in humans. IMPACT: This study reports the detection of chlormequat, an agricultural chemical with developmental and reproductive toxicity, in the U.S. population and U.S. food supplies for the first time. While similar levels of the chemical were found in urine sampled from 2017 to 2022, markedly increased levels were found in samples from 2023. This work highlights the need for more expansive monitoring of chlormequat in U.S. foods and in human specimens, as well as toxicological and epidemiological study on chlormequat, as this chemical is an emerging contaminant with documented evidence of low-dose adverse health effects in animal studies.

Reproductive and developmental toxicity of plant growth regulators in humans and animals

Plant growth regulators (PGRs) are currently one of the widely used pesticides, as being considered to have relatively low toxicity compared with other pesticides. However, widespread use may lead to overexposure from multiple sources. Exposure to PGRs is associated with different toxicity that affects many organs in our body, such as the toxicity to testis, ovaries, liver, kidneys and brain. In addition, some PGRs are considered potential endocrine disrupting chemicals. Evidence exists for development and reproductive toxicity associated with prenatal and postnatal exposure in both animals and humans. PGRs can affect the synthesis and secretion of sex hormones, destroy the structure and function of the reproductive system, and harm the growth and development of offspring, which may be related to germ cell cycle disorders, apoptosis and oxidative stress. This review summaries the reproductive and developmental toxicity data available about PGRs in mammals. In the future, conducting comprehensive epidemiological studies will be crucial for assessing the reproductive and developmental toxicity resulting from a mixture of various PGRs, with a particular emphasis on understanding the underlying molecular mechanisms.

Residue of Chlormequat and Regulatory Effects on the Specialized Metabolites of Astragali Radix

Presently, the utilization of chlormequat in Astragalus mongholicus Bunge (Leguminosae) cultivation is prevalent for augmenting rhizome (Astragali Radix) yield. However, indiscriminate and excessive chlormequat employment can detrimentally influence Astragali Radix quality and safety. This research aimed to comprehensively comprehend chlormequat risks and its influence on Astragali Radix metabolites. Diverse chlormequat concentrations were employed in Astragalus mongholicus cultivation, with subsequent analysis of residual chlormequat levels in Astragali Radix across treatment groups. Astragali Radix metabolic profiling was conducted through UPLC-QTOF-MS, and thirteen principal active components were quantified via UFLC-MS/MS. Findings revealed a direct correlation between chlormequat residue levels in Astragali Radix and application concentration, with high-dose residue surpassing 5.0 mg/kg. Metabolomics analysis identified twenty-six distinct saponin and flavonoid metabolites. Notably, the application of chlormequat led to the upregulation of seven saponins (e.g., astragaloside I and II) and downregulation of six flavonoids (e.g., methylnissolin-3-O-glucoside and astraisoflavan-7-O-β-d-glucoside). Quantitative analysis demonstrated variable contents of active ingredients due to differing chlormequat concentrations, leading to astragaloside I increase (14.59-62.55%) and isoastragaloside II increase (4.8-55.63%), while methylnissolin-3-O-glucoside decreased (22.18-41.69%), as did astraisoflavan-7-O-β-d-glucoside (21.09-47.78%). In conclusion, chlormequat application influenced multiple active components in Astragali Radix, causing constituent proportion variations. Elevated chlormequat concentrations led to increased active components alongside heightened chlormequat residues in Astragali Radix. Consequently, prudent chlormequat application during Astragali Radix production is imperative to avert potential detriments to its quality and safety.

Chlorocholine chloride induced testosterone secretion inhibition mediated by endoplasmic reticulum stress in primary rat Leydig cells

Chlorocholine chloride (CCC) is well acknowledged as a plant growth regulator and may be considered as a potential environmental endocrine disrupting chemical. In our previous studies, it was found that CCC exposure at a pubertal stage reduced the serum and testicular levels of testosterone, decreased the sperm motility and delayed the puberty onset. However, the molecular mechanisms of CCC-induced testosterone secretion disorders remain unclear. In this study, we found that CCC exposure above 20 μg/mL inhibited the secretion of testosterone in Sprague-Dawley rats Leydig cells. Proteomic and pathway enrichment analysis indicated that CCC might induce endoplasmic reticulum (ER) stress. Western blot detection showed CCC exposure at 100, 200 μg/mL increased the protein level of glucose-regulated protein 78 (GPR78), C/EBP-homologous protein (CHOP), the ubiquitin-conjugating enzyme E2 D1 (UBE2D1) and the ring finger protein (RNF185) in the Leydig cells. The Leydig cells treated with 4-phenyl butyric acid (4-PBA), an ER stress inhibitor, rescued the testosterone secretion disorders and alleviated CCC-induced increase in the ER stress related protein levels at 200 μg/mL CCC treatment. Overall, CCC in vitro exposure might disturb testosterone production of Leydig cells and endoplasmic reticulum stress was involved in it.

Effects of prenatal chlorocholine chloride exposure on pubertal development and reproduction of male offspring in rats

Chlorocholine chloride (CCC) promote plant growth as a regulator. Emerging evidence by our group showed that CCC might restrain the puberty onset and impair the reproductive functions in male rats through HPT axis. In this study, we further investigated the effects of prenatal CCC exposure on pubertal development, reproduction of male offspring in rats and explored the underlying mechanisms. The results showed that CCC of 137.5 and 200 mg/kg bw/day delayed the age of preputial separation (PPS), decreased the sperm motility of male offspring. PP1γ2 which is an essential protein in spermatogenesis reduced in 137.5 and 200 mg/kg bw/day groups. Crucial hormones involved in hypothalamic-puititary-testicular (HPT) axis decreased at postnatal day (PND) 30. It was indicated that CCC exposure in pregnancy might disturb the pubertal development, reproductive functions of male offspring through HPT axis and disturb the sperm motility through PP1γ2.

Protective effect of myricetin on nonylphenol-induced testicular toxicity: biochemical, steroidogenic, hormonal, spermatogenic, and histological-based evidences

Nonylphenol (NP) is an environmental contaminant, which induces testicular toxicity through oxidative stress. Myricetin (MYR) is a naturally occurring flavonol having powerful antioxidant activity. The current research was planned to examine the ameliorative role of MYR against NP-induced testicular damage. A total of 24 adult male Sprague-Dawley rats were randomly divided into 4 equivalent groups: control (0.1% DMSO), NP group (50 mg kg-1), NP + MYR group (50 mg kg-1; 100 mg kg-1), and MYR-treated group (100 mg kg-1). NP administration significantly (p < 0.05) decreased the activity of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR), and protein content while significantly (p < 0.05) elevating the thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) levels. Additionally, NP significantly (p < 0.05) reduced the sperm motility, gene expression of testicular steroidogenic enzymes (3β-HSD, 3β-hydroxysteroid dehydrogenase; 17β-HSD, 17β-hydroxysteroid dehydrogenase; StAR, steroidogenic-acute regulatory protein), level of luteinizing hormone (LH), follicle-stimulating hormone (FSH), plasma testosterone, and daily sperm production (DSP). On the other hand, it raised the testicular cholesterol, dead sperms, and head, midpiece, and tail abnormalities along with abnormal histomorphometry. However, MYR remarkably abrogated NP-induced damages. In conclusion, the outcomes of the study suggest that MYR can effectively alleviate the NP-induced oxidative stress and testicular damages.

Iprodione and chlorpyrifos induce testicular damage, oxidative stress, apoptosis and suppression of steroidogenic- and spermatogenic-related genes in immature male albino rats

The fungicide iprodione (IPR) and the insecticide chlorpyrifos (CPF) are concurrently applied for early disease control in fruits and other crops. However, there are no available data about the impacts of their co-exposure. Additionally, IPR and CPF are known as endocrine disruptors that can cause reproductive toxicity. The outcomes of their co-exposure on the development of male reproductive organs are still unknown. Therefore, this study aimed to assess the risk of exposure to these pesticides, particularly on the postnatal development of the male albino rat reproductive system from postnatal days 23-60. The results revealed that a single IPR or CPF exposure has harmful consequences on the reproductive development and function manifested by reduced testicular weight, serious changes in sperm characteristics, reproductive hormone level imbalance, testicular enzymes, oxidative stress and apoptosis-related enzymes, which correlated with transcription levels of steroidogenic- and spermatogenic-related genes. Histopathologically, both compounds caused severe damage in the testis and accessory glands architecture. Notably, co-exposure to IPR and CPF in rats caused more serious damage, indicative of an additive effect than individual exposure, so concurrent exposure should be avoided as it is more hazardous, especially on male fertility.

Environmental contaminants and male infertility: Effects and mechanisms

The escalating prevalence of male infertility and decreasing trend in sperm quality have been correlated with rapid industrialisation and the associated discharge of an excess of synthetic substances into the environment. Humans are inevitably exposed to these ubiquitously distributed environmental contaminants, which possess the ability to intervene with the growth and function of male reproductive organs. Several epidemiological reports have correlated the blood and seminal levels of environmental contaminants with poor sperm quality. Numerous in vivo and in vitro studies have been conducted to investigate the effect of various environmental contaminants on spermatogenesis, steroidogenesis, Sertoli cells, blood-testis barrier, epididymis and sperm functions. The reported reprotoxic effects include alterations in the spermatogenic cycle, increased germ cell apoptosis, inhibition of steroidogenesis, decreased Leydig cell viability, impairment of Sertoli cell structure and function, altered expression of steroid receptors, increased permeability of blood-testis barrier, induction of peroxidative and epigenetic alterations in spermatozoa resulting in poor sperm quality and function. In light of recent scientific reports, this review discusses the effects of environmental contaminants on the male reproductive function and the possible mechanisms of action.