Deregulation of autophagy is involved in nephrotoxicity of arsenite and fluoride exposure during gestation to puberty in rat offspring

Prenatal arsenic exposure alters EZH2/H3K27me3 to induce RKIP/NF-kB/ERK1/2-mediated early-onset kidney disease in mouse offspring

The rising incidences of chronic kidney disease (CKD) and renal failure are a major public health concern. Arsenic, a widespread water contaminant and environmental toxicant, is well-known to contribute to kidney disease in adults. However, its long-term effects on kidney health following early-life exposure remain poorly understood. Therefore, we investigated the impact of prenatal arsenic exposure on kidney health in offspring using a BALB/c mouse model. 0.4 ppm arsenic, an environmentally relevant dose, was orally administered to female mice from 15 days before mating until delivery. Structural and ultrastructural changes in the kidney were assessed using histopathology and transmission electron microscopy, while markers of inflammation, kidney injury, and function were evaluated through Luminex assays, FITC-sinistrin-based glomerular filtration rate (GFR), real-time PCR, immunohistochemistry, and immunoblotting. Notably, arsenic-exposed offspring showed reduced body weight, crown-to-rump length, inflammation, and early signs of kidney injury on postnatal day 2 (PND-2). By 6 weeks, examination showed tubular dilation, mitochondrial damage, vacuolated cytoplasm, and basement membrane disruption were more evident in the kidneys. Furthermore, elevated levels of kidney injury markers, including kidney injury molecule-1, beta-2 microglobulin, cystatin C, and tissue inhibitor of metalloproteinase 1, were detected in urine. These changes were accompanied by increased serum creatinine and a decline in kidney function, as evidenced by reduced GFR levels. Proinflammatory cytokines (TNF-α, IL-6) and NF-κB were significantly elevated along with an increased immune cell infiltration in the kidneys of arsenic-exposed offspring. Further analysis showed increased mesenchymal markers fibronectin and alpha-smooth muscle actin and reduced epithelial marker E-cadherin in the kidneys, indicating fibrosis and epithelial-to-mesenchymal transition. Mechanistic studies revealed that arsenic exposure leads to increased levels of epigenetic regulators enhancer of zeste homolog 2 (EZH2) and histone H3 lysine 27 trimethylation (H3K27me3), which were associated with the activation of inflammatory pathways, fibrosis, and impaired kidney function. Overall, our findings demonstrate that only developmental exposure to arsenic can cause dysregulation of EZH2 and H3K27me3, driving inflammation and renal fibrosis. These changes ultimately lead to chronic kidney disease in offspring, highlighting a critical window of vulnerability for arsenic toxicity with significant implications for long-term kidney health.

Arsenic Exposure-Induced Acute Kidney Injury by Regulating SIRT1/PINK1/Mitophagy Axis in Mice and in HK-2 Cells

Groundwater resources are often contaminated by arsenic, which poses a serious threat to human and animal's health. Some studies have demonstrated that acute arsenic exposure could induce kidney injury because the kidney is a key target organ for toxicity, but the exact mechanism remains unclear. Hence, we investigated the effect of SIRT1-/PINK1-mediated mitophagy on NaAsO2-induced kidney injury in vivo and in vitro. In our study, NaAsO2 exposure obviously induced renal tubule injury and mitochondrial dysfunction. Meanwhile, NaAsO2 exposure could inhibit the mRNA/protein level of SIRT1 and activate the mitophagy-related mRNA/protein levels in the kidney of mice. In HK-2 cells, we also confirmed that NaAsO2-induced nephrotoxicity depended on the activation of mitophagy. Moreover, the activation of SIRT1 by resveratrol alleviated NaAsO2-induced acute kidney injury via the activation of mitophagy in vivo and in vitro. Interestingly, the inhibition of mitophagy by cyclosporin A (CsA) further exacerbated NaAsO2-induced nephrotoxicity and inflammation in HK-2 cells. Taken together, our study found that SIRT1-regulated PINK1-/Parkin-dependent mitophagy was implicated in NaAsO2-induced acute kidney injury. In addition, we confirmed that PINK1-/Parkin-dependent mitophagy played a protective role against NaAsO2-induced acute kidney injury. Therefore, activation of SIRT1 and mitophagy may represent a novel therapeutic target for the prevention and treatment of NaAsO2-induced acute renal injury.

Identifying Serum Metabolites and Gut Bacterial Species Associated with Nephrotoxicity Caused by Arsenic and Fluoride Exposure

Co-contamination of arsenic (As) and fluoride (F) is widely distributed in groundwater, which are known risk factors for the nephrotoxicity. Emerging evidence has linked environmentally associated nephrotoxicity with the disturbance of gut microbiota and blood metabolites. In this study, we generated gut microbiota and blood metabolomic profile and identified multiple serum metabolites and gut bacteria species, which were associated with kidney injury on rat model exposed to As and F alone or combined. Combined As and F exposure significantly increased creatinine level. Abnormal autophagosomes and lysosome were observed, and the autophagic genes were enhanced in kidney tissue after single and combined As and F exposure. The metabolome data showed that single and combined As and F exposure remarkably altered the serum metabolites associated with the proximal tubule reabsorption function pathway, with glutamine and alpha-ketoglutarate level decreased in all exposed group. Furthermore, phosphatidylethanolamine (PE), the key contributor of autophagosomes, was decreased significantly in As and F + As exposed groups during the screen of autophagy-animal pathway. Multiple altered gut bacterial microbiota at phylum and species levels post As and F exposure were associated with targeted kidney injury, including p_Bacteroidetes, s_Chromohalobacter_unclassified, s_Halomonas_unclassified, s_Ignatzschineria_unclassified, s_Bacillus_subtilis, and s_Brevundimonas_sp._NA6. Meanwhile, our analysis indicated that As and F co-exposure possessed an interactive influence on gut microbiota. In conclusion, single or combined As and F exposure leads to the disruption of serum metabolic and gut microbiota profiles. Multiple metabolites and bacterial species are identified and associated with nephrotoxicity, which have potential to be developed as biomarkers of As and/or F-induced kidney damage.

A Facile Crystallization Strategy to Turn Calcium Bisphosphonates into Novel Osteogenesis-Inducing Biomaterials

Insoluble metal bisphosphonates (BPs) are considered an ideal alternative to the soluble counterparts in regenerative medicine due to their increased BP release profile, but still present undesired properties (e.g., low stability, uncontrolled degradation, and poor biocompatibility). Through a simple crystallization on a solid calcium hydroxyapatite (HA)-based substrate from a BP precursor solution in 30 days, a series of insoluble calcium BP (CaBP) crystals are developed. These crystals, including calcium alendronate (CaAln), calcium pamidronate (CaPam), calcium incadronate (CaInc), calcium risedronate (CaRis), calcium zoledronate (CaZol), and calcium di-minodronate (Ca(Min)2 ), present high purity, regular morphologies and excellent biodegradability. It is demonstrated that these CaBPs can induce osteogenic differentiation of adipose-derived mesenchymal stem cells in vitro in the absence of other osteogenic inducers. It is further found that CaBP induces bone formation more effectively in a femur defect rabbit model in three months but with a lower in vivo hematotoxicity than the clinically used HA during osteogenesis. It is believed that these desired biological properties arise from the capability of the insoluble CaBPs in releasing BPs in a sustained manner for stimulating osteogenesis. This work provides a significant strategy for turning CaBPs into novel biomaterials for tissue regeneration and demonstrates their great potential in the clinic.

Fluoride induces osteoblast autophagy by inhibiting the PI3K/AKT/mTOR signaling pathway in vivo and in vitro

Fluorosis primarily manifests as bone damage in the form of dental fluorosis and skeletal fluorosis and represents a critical global public health challenge. However, few studies have examined autophagy-related signaling pathways in skeletal fluorosis. This study aimed to investigate the effect of fluoride on autophagy in osteoblasts using comprehensive methods and to explore the role of the PI3K/AKT/mTOR signaling pathway in regulating fluoride-induced autophagy in osteoblasts. Sprague-Dawley (SD) rats were exposed to different concentrations of fluoride (NaF: 5, 50, and 100 mg/L) for six months. Primary osteoblasts were treated with 0.5, 1.0, or 3.0 mM NaF. Hematoxylin and eosin (H&E) staining, transmission electron microscopy (TEM), immunohistochemistry (IHC), immunofluorescence staining, and western blotting were performed to evaluate morphological changes in bone tissues and autophagosomes and to detect the protein expression of autophagy-related markers and PI3K/AKT/mTOR signaling pathway-related molecules both in vivo and in vitro. The bone tissues of fluoride-exposed rats showed osteosclerosis, autophagosomes and autolysosomes. LC3B immunofluorescence staining revealed an increase in autophagosomes in the primary osteoblasts treated with fluoride. The LC3Ⅱ/Ⅰ ratio and levels of autophagy-related markers (Beclin 1 and Atg7) were increased, whereas P62 levels were decreased in bone tissues and primary osteoblasts in the fluoride groups. Simultaneously, p-AKT and p-mTOR levels were reduced in bone tissues and primary osteoblasts in the fluoride groups. Moreover, a PI3K inhibitor (LY294002) further downregulated p-AKT and p-mTOR protein expression but slightly increased the LC3Ⅱ/Ⅰ ratio in primary osteoblasts. These results demonstrate that fluoride induces autophagy in osteoblasts by inhibiting the PI3K/AKT/mTOR signaling pathway, which deepens our understanding of the molecular mechanisms underlying fluoride-induced bone damage and provides a theoretical basis for the prevention and treatment of skeletal fluorosis.

Nephroprotective Effects of Selenium Nanoparticles Against Sodium Arsenite-Induced Damages

Introduction

The potential effects of selenium nanoparticles (SeNPs) administration on arsenic exposure-mediated nephrotoxicity by alleviating fibrosis, inflammation, oxidative stress-related damage, and apoptosis remains more detailed investigations.

Methods

After the synthesis of selenium nanoparticles (SeNPs) by sodium selenite (Na₂SeO₃) through a versatile and green procedure, the biosafety of SeNPs was assessed by assaying renal functions and inflammation in mice. Subsequently, nephroprotective effects of SeNPs against sodium arsenite (NaAsO₂)-induced damages were confirmed by biochemical, molecular, and histopathological assays, including renal function, histological lesion, fibrosis, inflammation, oxidative stress-related damage, and apoptosis in mice renal tissues and renal tubular duct epithelial cells (HK2 cells).

Results

The excellent biocompatibility and safety of SeNPs prepared in this study were confirmed by the non-significant differences in the renal functions and inflammation levels in mice between the negative control (NC) and 1 mg/kg SeNPs groups (p>0.05). The results of biochemical, molecular, and histopathological assays confirmed that daily administration of 1 mg/kg SeNPs for 4 weeks not only ameliorated renal dysfunctions and injuries caused by NaAsO₂ exposure but also inhibited the fibrosis, inflammation, oxidative stress-related damage, and apoptosis in the renal tissues of NaAsO₂-exposed mice. In addition, altered viability, inflammation, oxidative stress-related damage, and apoptosis in the NaAsO₂-exposed HK2 cells were effectively reversed after 100 μg/mL SeNPs supplementation.

Conclusion

Our findings authentically confirmed the biosafety and nephroprotective effects of SeNPs against NaAsO₂ exposure-induced damages by alleviating inflammation, oxidative stress-related damage, and apoptosis.

Co-exposure to arsenic and fluoride to explore the interactive effect on oxidative stress and autophagy in myocardial tissue and cell

Co-contamination of arsenic and fluoride is widely distributed in groundwater. However, little is known about the interactively influence of arsenic and fluoride, especially the combined mechanism in cardiotoxicity. Cellular and animal models exposure to arsenic and fluoride were established to assess the oxidative stress and autophagy mechanism of cardiotoxic damage using the factorial design, a widely used statistical method for assessing two factor interventions. In vivo, combined exposure to high arsenic (50 mg/L) and high fluoride (100 mg/L) induced myocardial injury. The damage is accompanied by accumulation of myocardial enzyme, mitochondrial disorder, and excessive oxidative stress. Further experiment identified that arsenic and fluoride induced the accumulation of autophagosome and increased expression level of autophagy related genes during the cardiotoxicity process. These findings were further demonstrated through the in vitro model of arsenic and fluoride-treated the H9c2 cells. Additionally, combined of arsenic-fluoride exposure possesses the interactively influence on oxidative stress and autophagy, contributing to the myocardial cell toxicity. In conclusion, our data suggest that oxidative stress and autophagy are involved in the process of cardiotoxic injury, and that these indicators showed interaction effect in response to the combined exposure of arsenic and fluoride.

Fluoride in the Central Nervous System and Its Potential Influence on the Development and Invasiveness of Brain Tumours-A Research Hypothesis

The purpose of this review is to attempt to outline the potential role of fluoride in the pathogenesis of brain tumours, including glioblastoma (GBM). In this paper, we show for the first time that fluoride can potentially affect the generally accepted signalling pathways implicated in the formation and clinical course of GBM. Fluorine compounds easily cross the blood-brain barrier. Enhanced oxidative stress, disruption of multiple cellular pathways, and microglial activation are just a few examples of recent reports on the role of fluoride in the central nervous system (CNS). We sought to present the key mechanisms underlying the development and invasiveness of GBM, as well as evidence on the current state of knowledge about the pleiotropic, direct, or indirect involvement of fluoride in the regulation of these mechanisms in various tissues, including neural and tumour tissue. The effects of fluoride on the human body are still a matter of controversy. However, given the growing incidence of brain tumours, especially in children, and numerous reports on the effects of fluoride on the CNS, it is worth taking a closer look at these mechanisms in the context of brain tumours, including gliomas.

Effects of Co-exposure to Fluoride and Arsenic on TRAF-6 Signaling and NF-κB Pathway of Bone Metabolism

Little is known about the combined effect of fluoride (F) and arsenic (As) on bone metabolism. This study aims to explore the effect of co-exposure to F and As on the expressions of TNF receptor-associated factor 6 (TRAF-6), nuclear factor-kappa B (NF-κB), and the related factors in cell and animal experiments. With the rats exposed to different doses of F, As, and combined F-As, we found that F exposure doses were positively correlated with the protein expression of receptor activator of nuclear factor-kappa B ligand (RANKL), receptor activator of nuclear factor-kappa B (RANK), TRAF-6, NF-κB, and nuclear factor of activated T cells (NFAT-c1) (P < 0.001). As exposure doses were negatively correlated with RANK, TRAF-6, NF-κB, and NFAT-c1 (P < 0.001). The effect of F and As interaction on the protein expression of RANKL, TRAF-6, NF-κB, and NFAT-c1 was significant in bone tissue (P < 0.05). In the cellular experiment, F could promote the mRNA expression of RANK, TRAF-6, and NFAT-c1. A higher concentration of As could inhibit the mRNA expression of Tartrate-resistant acid phosphatase (TRAP), RANK, TRAF-6, and NFAT-c1. The effect of F and As interaction on the mRNA expression of TRAP, RANK, TRAF-6, and NFATc1 in osteoclasts was significant (P < 0.001). In conclusion, the expression of TRAF-6 and NF-κB pathway was affected by F and As co-exposure in osteogenic differentiation, and As could antagonize the promoting effect of F on the expression of TRAF-6, TRAP, RANKL, RANK, NF-κB, and NFAT-c1 in these exposure levels. These results could provide a scientific basis for understanding the interaction of F and As in bone formation.

Effects of neuron autophagy induced by arsenic and fluoride on spatial learning and memory in offspring rats

There are numerous studies showing that exposure to arsenic (As) or fluoride (F) damages the nervous system, but there is no literature investigating the effects of combined As and F exposure to induce autophagy on neurotoxicity in the offspring. In this study, we developed a rat model of As and/or F exposure through drinking water from before pregnancy to 90 days postnatal. The offspring rats were randomly divided into nine groups. Sodium arsenite (NaAsO₂) (0, 35, 70 mg/L) and Sodium fluoride (NaF) (0, 50, 100 mg/L) were designed according to 3 × 3 factorial design. Our results suggested that the presence of F might antagonize the excretion of total As in urine, and As-F co-exposure led to severe pathological damage in brain tissue and reduced spatial learning and memory ability. At the same time, the experiments showed that As and F increased Beclin1 expression and LC3B ratio to activate autophagy; both P62 and Lamp2 expression were increased, suggesting that autophagy lysosomal degradation was blocked; SYN and JIP1 expression were significantly decreased, disrupting synaptic structure and function. Axonal autophagosome reverse transport regulation might be affected by combined As-F exposure, exacerbating neuronal synaptic damage and inducing neurotoxicity. Further analysis showed that there was an interaction between As and F exposure-induced changes in autolysosome-related proteins in the hippocampus, which showed antagonism, and the antagonism of the high As combined exposure groups were stronger than that of the low As combined exposure groups. In conclusion, our study showed that combined As and F exposure might induce reverse transport impairment of autophagy on axons, leading to autophagy defects, which in turn led to disruption of synaptic morphology and function, induced neurotoxicity, and there was an interaction between As and F, the type of its combined effect was antagonism.

Moderate exercise relieves fluoride-induced liver and kidney inflammatory responses through the IKKβ/NFκB pathway

With the intensification of environmental pollution, the content of fluoride is increasing in human and animal living environments. Long-term fluoride exposure can cause damage to the liver and kidney, which are the main sites for fluoride metabolism, storage and removal. Moreover, exercise often accompanies the entire process of fluoride exposure in humans and animals. However, the mechanism of exercise on fluoride-induced liver and kidney injury remains unclear. Hence, we established a fluoride exposure and/or exercise mouse model to explore the influence of exercise on fluoride-induced liver and kidney inflammation and the potential mechanism. The results showed that fluoride caused obvious structural and functional damage and the notable recruitment of immunocytes in the liver and kidney. In addition, fluoride increased the levels of IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL-13, IL-21, TNF-α, and TGF-β but decreased the ratio of IFN-γ/IL-4 and IL-2/IL-10, which indicated that fluoride disturbed the inflammatory balance and caused hepatonephritis. In addition, the expression levels of IKKβ and NFκB were increased, and the expression of IκBα was decreased after fluoride exposure, indicating that fluoride activated the IKKβ/NFκB pathway. In summary, long-term moderate treadmill exercise relieved fluoride-induced liver and kidney inflammatory responses through the IKKβ/NFκB pathway, and exercise can be used to prevent fluoride-induced liver and kidney damage.

Natural phytochemicals that affect autophagy in the treatment of oral diseases and infections: A review

Autophagy is a critical factor in eukaryotic evolution. Cells provide nutrition and energy during autophagy by destroying non-essential components, thereby allowing intracellular material conversion and managing temporary survival stress. Autophagy is linked to a variety of oral disorders, including the type and extent of oral malignancies. Furthermore, autophagy is important in lymphocyte formation, innate immunity, and the regulation of acquired immune responses. It is also required for immunological responses in the oral cavity. Knowledge of autophagy has aided in the identification and treatment of common oral disorders, most notably cancers. The involvement of autophagy in the oral immune system may offer a new understanding of the immune mechanism and provide a novel approach to eliminating harmful bacteria in the body. This review focuses on autophagy creation, innate and acquired immunological responses to autophagy, and the status of autophagy in microbial infection research. Recent developments in the regulatory mechanisms of autophagy and therapeutic applications in oral illnesses, particularly oral cancers, are also discussed. Finally, the relationship between various natural substances that may be used as medications and autophagy is investigated.

DNA Methylation Profiles of Ovarian Granular Cells from Fluorosis Female Patients Suffering Reproductive Dysfunctions

Fluorosis often causes female reproductive dysfunction. A rapid turnover of DNA methylation is a pathological change in many human diseases, including female reproductive dysfunction. The role of DNA methylation in fluorosis was unknown and investigated in this experiment. Fifty fluorosis women patients were selected as High F group and forty-six healthy women were recruited as Control group were enrolled. In addition, ovarian granulosa cells were obtained from five women in High F group and five women in Control group. All ten women went through in vitro fertilization (IVF) process with DNA methylation sequencing. KGN cells (human granulosa cell line) were cultured with different concentrations of sodium fluoride (0-8 mM NaF) for 24 h for the in vitro study. The level of DNA methylation in blood samples was significantly higher in High F group than that in Control group. The level of serum estradiol (E₂) was significantly lower in women from High F group, while the levels of serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in High F group were significantly higher than that in Control group. The methylation sequences of KGN cells relating to autophagy were significantly changed by NaF treatment dose-dependently. Based on these results, it is concluded that DNA methylation and autophagy may play a significant role in the pathophysiology of reproductive dysfunction caused by fluorosis.

Solving the riddle of Aguascalientes nephropathy: nephron number, environmental toxins and family clustering

Aguascalientes, Mexico, has a high incidence and prevalence of advanced chronic kidney disease (CKD). CKD is especially frequent in young people ages 20-40 years in whom the cause of CKD was unknown, although kidney biopsies frequently showed focal segmental glomerulosclerosis (FSGS) and glomerulomegaly. Macias-Diaz et al. have now pursued this lead by screening teenagers in Calvillo, one of the hardest hit municipalities. They uncovered clinical, laboratory, kidney biopsy and exposure findings that define a new entity, Aguascalientes nephropathy, and are consistent with familial exposure to common environmental toxins, potentially consisting of pesticides. They hypothesize that prenatal exposure to these toxins may decrease nephron number. The young age of persons with FSGS would be consistent with a novel environmental toxin introduced more than 50 years ago but not present in the environment before. Key takeaways from this research are the need to screen teenagers for albuminuria, to provide kidney-protective strategies to patients identified as having CKD and for the research community to support Aguascalientes nephrologists and health authorities to unravel the cause and potential solutions for this CKD hotspot. In this regard, the screening approach and the cohort generated by Macias-Diaz et al. represent a giant step forward. The next steps should be to screen younger children for albuminuria and kidney size and to identify the putative toxins.

Challenges of fluoride pollution in environment: Mechanisms and pathological significance of toxicity - A review

Fluoride is an important trace element in the living body. A suitable amount of fluoride has a beneficial effect on the body, but disproportionate fluoride entering the body will affect various organs and systems, especially the liver, kidneys, nervous system, endocrine system, reproductive system, bone, and intestinal system. In recent years, with the rapid development of agriculture and industry, fluoride pollution has become one of the important factors of environmental pollution, and fluoride pollution in any form is becoming a serious problem. Although countries around the world have made great breakthroughs in controlling fluoride pollution, however fluorosis still exists. A large amount of fluoride accumulated in animals will not only produce the toxic effects, but it also causes cell damage and affect the normal physiological activities of the body. There is no systematic description of the damage mechanism of fluoride. Therefore, the study on the toxicity mechanism of fluoride is still in progress. This review summarizes the existing information of several molecular mechanisms of the fluoride toxicity comprehensively, aiming to clarify the toxic mechanism of fluoride on various body systems. We have also summerized the pathological changes of those organ systems after fluoride poisoning in order to provide some ideas and solutions to the reader for the prevention and control of modern fluoride pollution.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Aguascalientes: one of the hottest chronic kidney disease (CKD) hotspots in Mexico and a CKD of unknown aetiology mystery to be solved

In a recent issue of Clinical Kidney Journal (CKJ), Gutierrez-Peña et al. reported a high incidence and prevalence of advanced chronic kidney disease (CKD) in Aguascalientes, Mexico. This contradicts Global Burden of Disease estimates, which should be updated. A key component of this high burden of CKD relates to young people ages 20-40 years in whom the cause of CKD was unknown [CKD of unknown aetiology (CKDu)]. The incidence of kidney replacement therapy in this age group in Aguascalientes is among the highest in the world, second only to Taiwan. However, high-altitude Aguascalientes, with a year-round average temperature of 19°C, does not fit the geography of other CKDu hotspots. Furthermore, kidney biopsies in young people showed a high prevalence of focal segmental glomerulosclerosis. Potential causes of CKDu in Aguascalientes include the genetic background (no evidence, although podocytopathy genes should be explored) and environmental factors. The highest prevalence of CKD was found in Calvillo, known for guava farming. Thus guava itself, known to contain bioactive, potentially nephrotoxic molecules and pesticides, should be explored. Additionally, there are reports of water sources in Aguascalientes contaminated with heavy metals and/or pesticides. These include fluoride (increased levels found in Calvillo drinking water) as well as naturally occurring arsenic, among others. Fluoride may accumulate in bone and cause kidney disease years later, and maternal exposure to excess fluoride may cause kidney disease in offspring. We propose a research agenda to clarify the cause of CKDu in Aguascalientes that should involve international funders. The need for urgent action to identify and stem the cause of the high incidence of CKD extends to other CKD hotspots in Mexico, including Tierra Blanca in Veracruz and Poncitlan in Jalisco.

Co-exposure to fluoride and arsenic disrupts intestinal flora balance and induces testicular autophagy in offspring rats

While numerous studies have shown that fluoride or arsenic exposure may damage the reproductive system, there are few reports of co-exposure to fluoride and arsenic. In addition, the literature on autophagy and intestinal flora composition in reproductive toxicity studies of co-exposure to fluoride and arsenic is insufficient. In this study, we developed a rat model of fluoride and arsenic exposure via drinking water from pre-pregnancy to 90 days postnatal. Sprague-Dawley rats were randomly divided into sterile water control group, fluoride group (100 mg/L NaF), arsenic group (50 mg/L NaAsO₂) and combined exposure group (100 mg/L NaF+50 mg/L NaAsO₂). Our results showed that fluoride and arsenic exposure caused a reduction in testicular weight and significant pathological damage to tissue. We found that the levels of follicle-stimulating hormone, luteinizing hormone, and testosterone were reduced to varying degrees. Meanwhile experiments showed that fluoride and arsenic exposure can modulate autophagic flux, causing increased levels of Beclin1 and LC3 expression and decreased p62 expression. Analogously, by performing 16S sequencing of rat feces, we found 24 enterobacterial genera that differed significantly among the groups. Furthermore, the flora associated with testicular injury were identified by correlation analysis of hormonal indices and autophagy alterations with intestinal flora composition at the genus level, respectively. In summary, our study shows that fluoride and arsenic co-exposure alters autophagic flux in the testis, causes testicular injury, and reveals an association between altered intestinal flora composition and testicular injury.

The potential risks of chronic fluoride exposure on nephrotoxic via altering glucolipid metabolism and activating autophagy and apoptosis in ducks

Fluoride is one of the most widely distributed elements in nature, while some fluorine-containing compounds are toxic to several vertebrates at certain levels. The current study was performed to evaluate the nephrotoxic effects of fluoride exposure in ducks. The results showed that the renal index was decreased in NaF group, and fluoride exposure significantly decreased the levels of serum Albumin, Glucose, Total cholesterol, Urea, protein and Triglycerides, confirming that NaF exhibited adverse effects on the kidney. The overall structure of renal cells showed damage with the signs of nuclelytic, vacuolar degeneration, atrophy, renal cystic cavity widening after fluoride induction. Renal vascular growth was impaired as the expression of VEGF and HIF-1α decreased (p > 0.05). More importantly, autophagy and apoptosis levels of CYT C, LC3, p62, Beclin, M-TOR, Bax and Caspase-3 were increased (p < 0.05) in the NaF treated group. Interestingly, our results showed that Phosphatidylethanolamine (PE) and Phosphatidylcholine (PC) activated the M-TOR autophagy pathway. Meanwhile, the PE acted on Atg5/ LC3 autophagy factor, followed by the auto-phagosome generation and activation of cell autophagy. These results indicate that NaF exposure to duck induced nephron-toxicity by activating autophagy, apoptosis and glucolipid metabolism pathways, which suggest that fluorine exposure poses a risk of poisoning.

The role of autophagy in metal-induced urogenital carcinogenesis

Environmental and/or occupational exposure to metals such as Arsenic (As), Cadmium (Cd), and Chromium (Cr) have been shown to induce carcinogenesis in various organs, including the urogenital system. However, the mechanisms responsible for metal-induced carcinogenesis remain elusive. We and others have shown that metals are potent inducers of autophagy, which has been suggested to be an adaptive stress response to allow metal-exposed cells to survive in hostile environments. Albeit few, recent experimental studies have shown that As and Cd promote tumorigenesis via autophagy and that inhibition of autophagic signaling suppressed metal-induced carcinogenesis. In light of the newly emerging role of autophagic involvement in metal-induced carcinogenesis, the present review focuses explicitly on the mechanistic role of autophagy and potential signaling pathways involved in As-, Cd-, and Cr-induced urogenital carcinogenesis.

Argan oil ameliorates sodium fluoride-induced renal damage via inhibiting oxidative damage, inflammation, and intermediate filament protein expression in male rats

Fluoride is widely distributed in the environment and has been associated with the development of different health hazards in animals and humans. Argan oil (AO) is a natural vegetable oil with various beneficial pharmacological effects. This study was designed to investigate the potential protective effect of AO supplementation as pre-treatment or co-treatment on sodium fluoride (NaF)-induced nephrotoxicity in rats. Male Sprague Dawley rats (n = 50) were randomly assigned to one of five equal groups: control group, AO-treated group (6 ml/kg b.wt.), NaF-treated group (20 mg/kg b.wt.), pre-treated group, and co-treated group. All rats were daily administered by oral gavage for duration of 30 days. The results showed that AO administration significantly improved renal function and antioxidant status and decreased the lipid peroxidation in NaF-treated rats. Additionally, AO normalized the renal levels of inflammatory markers and mRNA expression level of the intermediate filament protein genes, indicating NaF-induced podocyte damage was ameliorated. Histopathological evaluation of the kidney confirmed the before mentioned biochemical results. AO counteracted the nephrotoxic effects of NaF in rats particularly at co-exposure. These results concluded that AO administration exhibited a significant nephroprotective effect against renal injury induced by NaF in rats.