Correlation between 3-MCPD-induced organ toxicity and oxidative stress response in male mice

Boric Acid and Borax Protect Human Lymphocytes from Oxidative Stress and Genotoxicity Induced by 3-Monochloropropane-1,2-diol

3-chloro-1,2-propanediol (3-MCPD) is a member of the group of pollutants known as chloropropanols and is considered a genotoxic carcinogen. Due to the occurrence of 3-MCPD, which cannot be avoided in multiplexed food processes, it is necessary to explore novel agents to reduce or prevent the toxicity of 3-MCPD. Many recent studies on boron compounds reveal their superior biological roles such as antioxidant, anticancer, and antigenotoxic properties. In the current investigation, we have evaluated in vitro cytotoxic, oxidative, and genotoxic damage potential of 3-MCPD on human whole blood cultures and the alleviating effect of boric acid (BA) and borax (BX) for 72 h. In our in vitro experiments, we have treated blood cells with BA and BX (2.5, 5, and 10 mg/L) and 3-MCPD (at IC50 of 11.12 mg/l) for 72 h to determine the cytotoxic damage potential by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and lactate dehydrogenase (LDH) release assays. Oxidative damage was assessed using total antioxidant capacity (TAC) and malondialdehyde (MDA) levels. Genotoxicity evaluations were performed using chromosome aberrations (CAs) and 8-hydroxy deoxyguanosine (8-OHdG) assays. The result of our experiments showed that the 3-MCPD compound induced cytotoxicity, oxidative stress, and genotoxicity in a clear concentration-dependent manner. BA and BX reduced cytotoxicity, oxidative stress, and genotoxicity induced by 3-MCPD. In conclusion, BA and BX are safe and non-genotoxic under the in vitro conditions and can alleviate cytotoxic, oxidative, and genetic damage induced by 3-MCPD in the human blood cells. Our findings suggest that dietary boron supplements may offer a novel strategy for mitigating hematotoxicity induced by xenobiotics, including 3-MCPD.

EGCG Alleviates the Aging Toxicity Induced by 3-MCPD via IIS Pathway in Caenorhabditis elegans with Abnormal Reproduction and Heat Shock Protein

This study aimed to investigate the mitigation effect of epigallocatechin gallate (EGCG) on aging induced by 3-monochloropropane-1,2-diol (3-MCPD) in Caenorhabditis elegans, evaluate health indicators during the process, and reveal the underlying mechanism through transcriptomics and identification of mutants. The results showed that EGCG alleviated the declined fertility, shortened lifespan, reduced body size, weakened movement, increased reactive oxygen species and lipofuscin, and damaged antioxidative stress response and excessive heat shock proteins caused by 3-MCPD. Transcriptomics study indicated that treatment with 3-MCPD and EGCG altered gene expression, and gene mutants confirmed the involvement of insulin/IGF-1 signaling pathway in mediating the process that EGCG alleviated the aging toxicity induced by 3-MCPD. The study showed that EGCG alleviated the aging toxicity induced by 3-MCPD.

3-MCPD Induces Renal Cell Pyroptosis and Inflammation by Inhibiting ESCRT-III-Mediated Cell Repair and Mitophagy

3-Monochloropropane-1,2-diol (3-MCPD) is a chloropropyl alcohol contaminant mainly from the thermal processing of food and could affect kidneys. Pyroptosis is programmed cell death mediated by inflammasomes and gasdermins, and excessive cellular pyroptosis and inflammation can lead to tissue injury. In the present study, we found that 3-MCPD increased lactate dehydrogenase (LDH) levels in vitro and in vivo, increased the protein expression of NOD-like receptor family pyrin domain containing 3 (NLRP3), N-terminal domain of GSDMD (GSDMD-N), and cleaved caspase-1 and promoted the release of interleukin-1β (IL-1β) and interleukin-18 (IL-18), which induced renal cell pyroptosis and inflammation. Mechanistic studies indicated that the addition of N-acetylcysteine (NAC), a ROS scavenger, inhibited NLRP3 activation and attenuated pyroptosis. Furthermore, we revealed that 3-MCPD induced ROS accumulation by inhibiting ESCRT-III-mediated mitophagy. These results were further validated by the overexpression of charged multivesicular body protein 4B (CHMP4B), a key subunit of ESCRT-III, and the addition of the mitophagy activator carbonyl cyanide m-chlorophenylhydrazone (CCCP) and rapamycin (Rapa). Thus, our results showed that 3-MCPD could induce mitochondrial damage and produce ROS. 3-MCPD suppressed mitophagy, leading to the accumulation of damaged mitochondria and ROS, thereby activating NLRP3 and pyroptosis. Meanwhile, 3-MCPD-mediated suppression of ESCRT-III hindered the repair of GSDMD-induced cell membrane rupture, which further caused the occurrence of pyroptosis. Our findings provide new perspectives for studying the mechanisms underlying 3-MCPD-induced renal injury.

Mechanism of action of anthocyanin on the detoxification of foodborne contaminants-A review of recent literature

Foodborne contaminants refer to substances that are present in food and threaten food safety. Due to the progress in detection technology and the rising concerns regarding public health, there has been a surge in research focusing on the dangers posed by foodborne contaminants. These studies aim to explore and implement strategies that are both safe and efficient in mitigating the associated risks. Anthocyanins, a class of flavonoids, are abundantly present in various plant species, such as blueberries, grapes, purple sweet potatoes, cherries, mulberries, and others. Numerous epidemiological and nutritional intervention studies have provided evidence indicating that the consumption of anthocyanins through dietary intake offers a range of protective effects against the detrimental impact of foodborne contaminants. The present study aims to differentiate between two distinct subclasses of foodborne contaminants: those that are generated during the processing of food and those that originate from the surrounding environment. Furthermore, the impact of anthocyanins on foodborne contaminants was also summarized based on a review of articles published within the last 10 years. However, further investigation is warranted regarding the mechanism by which anthocyanins target foodborne contaminants, as well as the potential impact of individual variations in response. Additionally, it is important to note that there is currently a dearth of clinical research examining the efficacy of anthocyanins as an intervention for mitigating the effects of foodborne pollutants. Thus, by exploring the detoxification effect and mechanism of anthocyanins on foodborne pollutants, this review thereby provides evidence, supporting the utilization of anthocyanin-rich diets as a means to mitigate the detrimental effects of foodborne contaminants.

Rapid Sample Enrichment, Novel Derivatization, and High Sensitivity for Determination of 3-Chloropropane-1,2-diol in Soy Sauce via High-Performance Liquid Chromatography-Tandem Mass Spectrometry

A novel, simplified derivatization method and a rapid sample preparation process using carbon yarn as a sorbent for the determination of 3-chloropropane-1,2-diol (3-MCPD) in soy sauce via high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. 3-MCPD was first enriched and purified with carbon yarn and then eluted with a methanol-water solution. Subsequently, the analyte underwent derivatization with p-(dimethylamino)-phenol for sensitive detection via HPLC-MS/MS. The limit of detection and the limit of quantitation for 3-MCPD were validated to be 0.5 and 1.0 μg/kg, respectively. Spiking experiments showed recoveries between 83 and 94%, with a relative standard deviation of ≤10%. The method was further validated with a certified reference material. Furthermore, 11 real soy sauce samples from local markets were tested by using this method. These results reveal the widespread 3-MCPD contamination. Consequently, this study offers a preferable alternative for the sensitive, accurate, and precise determination of 3-MCPD in soy sauce.

3-MCPD Induced Mitochondrial Damage of Renal Cells Via the Rhythmic Protein BMAL1 Targeting SIRT3/SOD2

Biorhythm regulates a variety of physiological functions and enables organisms to adapt to changing environments. 3-Monochloro-1,2-propanediol (3-MCPD) is a common food thermal processing contaminant, and the kidney is its toxic target organ. However, the nephrotoxicity mechanism of 3-MCPD has not been fully elucidated. In the study, we found that 3-MCPD caused mitochondrial damage in renal cells by inhibiting the SIRT3/SOD2 pathway. Further, we found that 3-MCPD could interfere with rhythm protein BMAL1 expression at protein and mRNA levels in mice kidney and NRK-52E cells. Simultaneously, the balance of the daily oscillation of SIRT3/SOD2 pathway proteins was impeded under 3-MCPD treatment. To determine the role of BAML1 in mitochondrial damage, we overexpressed the BMAL1 protein. The data showed that BMAL1 overexpression upregulated SIRT3 and SOD2 expression and attenuated mitochondrial damage caused by 3-MCPD. These results indicated that 3-MCPD inhibited the SIRT3/SOD2 pathway by affecting the expression of the rhythm protein BMAL1, thereby inducing mitochondrial damage in renal cells. Taken together, our work reveals that 3-MCPD may possess a toxic effect via circadian clock mechanisms.

Potential of in vivo stress reporter models to reduce animal use and provide mechanistic insights in toxicity studies

Chemical risk assessment ensures protection from the toxic effects of drugs and manmade chemicals. To comply with regulatory guidance, studies in complex organisms are required, as well as mechanistic studies to establish the relevance of any toxicities observed to man. Although in vitro toxicity models are improving, in vivo studies remain central to this process. Such studies are invariably time-consuming and often involve large numbers of animals. New regulatory frameworks recommend the implementation of "smart" in vivo approaches to toxicity testing that can effectively assess safety for humans and comply with societal expectations for reduction in animal use. A major obstacle in reducing the animals required is the time-consuming and complexity of the pathological endpoints used as markers of toxicity. Such endpoints are prone to inter-animal variability, subjectivity and require harmonisation between testing sites. As a consequence, large numbers of animals per experimental group are required. To address this issue, we propose the implementation of sophisticated stress response reporter mice that we have developed. These reporter models provide early biomarkers of toxic potential in a highly reproducible manner at single-cell resolution, which can also be measured non-invasively and have been extensively validated in academic research as early biomarkers of stress responses for a wide range of chemicals at human-relevant exposures. In this report, we describe a new and previously generated models in our lab, provide the methodology required for their use and discuss how they have been used to inform on toxic risk (likelihood of chemical causing an adverse health effect). We propose our in vivo approach is more informative (refinement) and reduces the animal use (reduction) compared to traditional toxicity testing. These models could be incorporated into tiered toxicity testing and used in combination with in vitro assays to generate quantitative adverse outcome pathways and inform on toxic potential.

Potential of in vivo stress reporter models to reduce animal use and provide mechanistic insights in toxicity studies

Chemical risk assessment ensures protection from the toxic effects of drugs and manmade chemicals. To comply with regulatory guidance, studies in complex organisms are required, as well as mechanistic studies to establish the relevance of any toxicities observed to man. Although in vitro toxicity models are improving, in vivo studies remain central to this process. Such studies are invariably time-consuming and often involve large numbers of animals. New regulatory frameworks recommend the implementation of "smart" in vivo approaches to toxicity testing that can effectively assess safety for humans and comply with societal expectations for reduction in animal use. A major obstacle in reducing the animals required is the time-consuming and complexity of the pathological endpoints used as markers of toxicity. Such endpoints are prone to inter-animal variability, subjectivity and require harmonisation between testing sites. As a consequence, large numbers of animals per experimental group are required. To address this issue, we propose the implementation of sophisticated stress response reporter mice that we have developed. These reporter models provide early biomarkers of toxic potential in a highly reproducible manner at single-cell resolution, which can also be measured non-invasively and have been extensively validated in academic research as early biomarkers of stress responses for a wide range of chemicals at human-relevant exposures. In this report, we describe a new and previously generated models in our lab, provide the methodology required for their use and discuss how they have been used to inform on toxic risk (likelihood of chemical causing an adverse health effect). We propose our in vivo approach is more informative (refinement) and reduces the animal use (reduction) compared to traditional toxicity testing. These models could be incorporated into tiered toxicity testing and used in combination with in vitro assays to generate quantitative adverse outcome pathways and inform on toxic potential.

Evaluation of Physicochemical Properties of a Hydrocolloid-Based Functional Food Fortified with Caulerpa lentillifera: A D-Optimal Design Approach

This study introduced a D-optimal design mixture to assess the physicochemical properties of a hydrocolloid-based functional food fortified with C. lentillifera. The combination incorporated vital jelly constituents, including extract (10-15%), sweeteners (20-29%), gelling agents (k-carrageenan and locust bean gum (LBG)), and preservatives (0-0.05%). The dependent variables were pH, Total Soluble Solid (TSS) value, and moisture content (MS). By employing the D-optimal design approach, a quadratic polynomial model was developed, demonstrating strong correlations with the experimental data with coefficient determinations (R²) of 0.9941, 0.9907, and 0.9989 for pH, TSS, and MS, respectively. Based on the D-optimal design, the study identified the optimum combination of significant factors with a desirability of 0.917, comprising 14.35% extract, 23.00% sucrose, 21.70% fructose, 26.00% k-carrageenan, 13.00% LBG, 1.95% CaCl₂, and 0% methylparaben. The percentage of residual standard error (RSE) was less than 5%, indicating the reliability of the developed model. Furthermore, color analysis revealed significant differences among the jellies (p < 0.05). HPLC analysis demonstrated that the total sugar content in the fortified jellies was 28% lower compared to commercial jelly. Meanwhile, the bitterness level according to e-tongue showed a reduction of up to 90.5% when compared to the extract. These findings provide a valuable benchmark for the development of functional food products, ensuring their quality, safety, and extended shelf-life.

Lipidomics Analysis Explores the Mechanism of Renal Injury in Rat Induced by 3-MCPD

3-monochloropropane-1,2-diol (3-MCPD) is a food-process toxic substance, and its main target organ is the kidney. The present study examined and characterized the nephrotoxicity and the lipidomic mechanisms in a model of kidney injury in Sprague Dawley (SD) rats treated with high (45 mg/kg) and low (30 mg/kg) doses of 3-MCPD. The results showed that the ingestion of 3-MCPD led to a dose-dependent increase in serum creatinine and urea nitrogen levels and histological renal impairment. The oxidative stress indicators (MDA, GSH, T-AOC) in the rat kidney altered in a dose-dependent manner in 3-MCPD groups. The lipidomics analysis revealed that 3-MCPD caused kidney injury by interfering with glycerophospholipid metabolism and sphingolipid metabolism. In addition, 38 lipids were screened as potential biomarkers. This study not only revealed the mechanism of 3-MCPD renal toxicity from the perspective of lipidomics but also provided a new approach to the study of 3-MCPD nephrotoxicity.

Newly discovered developmental and ovarian toxicity of 3-monochloro-1,2-propanediol in Drosophila melanogaster and cyanidin-3-O-glucoside's protective effect

3-Monochloro-1,2-propanediol (3-MCPD) is a pervasive environmental pollutant that is unintentionally produced during industrial production and food processing. Although some studies reported the carcinogenicity and male reproduction toxicity of 3-MCPD thus far, it remains unexplored whether 3-MCPD hazards to female fertility and long-term development. In this study, the model Drosophila melanogaster was employed to evaluate risk assessment of emerging environmental contaminants 3-MCPD at various levels. We found that flies on dietary exposure to 3-MCPD incurred lethality in a concentration- and time-dependent way and interfered with metamorphosis and ovarian development, resulting in developmental retardance, ovarian deformity and female fecundity disorders. Mechanistically, 3-MCPD caused redox imbalance observed as a drastically increased oxidative status in ovaries, confirmed by increased reactive oxygen species (ROS) and decreased antioxidant activities, which is probably responsible for female reproductive impairments and developmental retardance. Intriguingly, these defects can be substantially prevented by a natural antioxidant, cyanidin-3-O-glucoside (C3G), further confirming a critical role of ovarian oxidative damage in the developmental and reproductive toxicity of 3-MCPD. The present study expanded the findings that 3-MCPD acts as a developmental and female reproductive toxicant, and our work provides a theoretical basis for the exploitation of a natural antioxidant resource as a dietary antidote for the reproductive and developmental hazards of environmental toxicants that act via increasing ROS in the target organ.

3-MCPD exposure enhances ovarian fibrosis and reduces oocyte quality in mice

3-monochloro-1,2-propanediol (3-MCPD) is a food contaminant believed to be harmful to human health. Previous studies showed that 3-MCPD exerts toxic effects in multiple tissues, but whether 3-MCPD affects female reproductive function remained unknown. Here, using mouse gastric lavage models, we report that 3-MCPD exposure for four weeks affected body growth, decreased the ovary/body weight ratio, and increased atretic follicle numbers. Expression levels of follicular development-related factors decreased. Further studies found that ovaries from 3-MCPD exposed mice had activated the Transforming Growth Factor-β (TGF-β) signaling pathway and promoted ovarian fibrosis. Increased TNF-α, IL-1 and NF-κB expression also indicated the occurrence of ovarian inflammation. Exposure to 3-MCPD stimulated the caspase pathway and enhanced granulosa cell apoptosis. Consistent with disrupted ovarian homeostasis, 3-MCPD exposure interfered with mitochondrial function, generated more reactive oxygen species, increased ferrous ion and lipid peroxidation levels, and resulted in decreased oocyte development potential. Collectively, these findings indicated that 3-MCPD exposure induced ovarian inflammation and fibrosis, and caused disorders of mitochondrial function and ferrous ion homeostasis in oocytes, which consequently disturbed follicle maturation and reduced oocyte quality.

Bibliometric Analysis of Research Trends on 3-Monochloropropane-1,2-Diol Esters in Foods

3-Monochloropropane-1,2-diol esters (3-MCPDE) are common food contaminants mainly formed in the edible oil refining process. Due to their potential hazards, 3-MCPDE has become a widespread food safety concern. In this study, CiteSpace and VOSviewer were used to conduct a bibliometric analysis on the 3-MCPDE research papers collected in the Web of Science Core Collection from 1998 to 2022. The results showed that the number of research publications on 3-MCPDE has increased rapidly since 2010. Analysis of the hotspots in 3-MCPDE studies showed that more attention has been paid to the exposure assessment, formation mechanism, detection methods, mitigation methods and toxicity, and toxicology of 3-MCPDE. Finally, the future trends of research on 3-MCPDE were analyzed and proposed. The mitigation methods and toxicology studies of 3-MCPDE are still the research hotspots in the future. In addition, nutritional intervention for 3-MCPDE toxicity will be an emerging trend.

Dysregulation of NrF2 expression mediates testicular injury and infertility in 3-monochloro-1,2-propandiol-intoxicated rats with special reference to accessory gland-related pathology

3-Monochloropropane-1,2-diol (3-MCPD) is a food contaminant formed during acid hydrolysis of vegetable proteins. The toxicological evaluation of smaller doses of 3-MCPD is essential for safety evaluation of this compound. The present study investigates the toxicologic potential of 3-MCPD on male genital organs of rats, applies a correlation between the induced infertility and developed lesions in testes, epididymis, and accessory glands and study the possible mechanisms of 3-MCPD-induced male infertility. Forty rats were randomly divided into four main groups of ten animals each: the control untreated group and three treated groups that were orally administered 3-MCPD at different doses (3, 7.5 and 15 mg/kg b.w) daily via stomach intubation for five successive days per week. Five rats from each group were euthanized after 30 days. The remaining rats were euthanized after 90 days to establish subacute and chronic toxicity studies. Oxidative stress markers, Nrf2 gene expression, semen analysis, and histopathological examination were performed at the end of each experimental period. Results indicated that 3-MCPD induces infertility in male rat via disruption of Nrf2 expression in the testicular tissue with subsequent increased oxidative stress indicators in the testis that affect spermatogenesis and induced testicular degeneration, in addition, induction of epididymal lesions that affect sperm motility and concentration and finally possible development of hyperplastic tissue reactions in accessory glands of intoxicated rats predicting the carcinogenic potential of this compound.

Nephrotoxicity evaluation of 3-monochloropropane-1,2-diol exposure in Sprague-Dawley rats using data-independent acquisition-based quantitative proteomics analysis

3-Monochloropropane-1,2-diol (3-MCPD), as a heat-induced food process contaminant, possesses strongly toxic effect on kidney. The present study focuses on characterizing the proteome and clarifying the underlying molecular regulatory mechanisms in a model of kidney injury in rats treated with 3-MCPD. Data-independent acquisition (DIA)-mass spectrometry (MS) based proteomics was used to identify dysregulated proteins in kidney tissues of Sprague-Dawley (SD) rats treated with 30 mg/kg/day 3-MCPD by gavage for 28 days. It was found that a total of 975 proteins were deregulated after 3-MCPD treatment. Bioinformatic analyses revealed that several enzymes related to the metabolisms of amino acid, lipid and carbohydrate in endogenous metabolism were altered in response to 3-MCPD treatment. Moreover, some proteins involved in these pathways were also changed, mainly including oxidative stress, oxidative phosphorylation, apoptosis and autophagy. Our study unravels the vital roles of loss of mitochondrial homeostasis and function and cell death pathways in the development of renal damage induced by 3-MCPD, which provides further valuable insights into the initiation and resolution of 3-MCPD nephrotoxicity. The proposed DIA-MS workflow not only provides a choice for proteomic analysis in toxicological research, but also provides a more comprehensive understanding of the molecular mechanisms of nephrotoxicity induced by toxins.

Diosgenin Protects Against Kidney Injury and Mitochondrial Apoptosis Induced by 3-MCPD Through the Regulation of ER Stress, Ca2+ Homeostasis, and Bcl2 Expression

SCOPE

Diosgenin (DIO) is a natural steroid sapogenin presented in various plants. It exerts anti-oxidant, anti-inflammatory and anti-diabetic nephropathy properties. The present study evaluates the intervention effect of DIO on nephrotoxicity induced by food contaminant 3-chloro-1, 2-propanediol (3-MCPD) in vivo and in vitro.

METHODS AND RESULTS

Treatment with DIO (15 mg kg-1 d-1 ) in Sprague-Dawley rats for 4-week relieves kidney injury induced by 3-MCPD (30 mg kg-1 d-1 ). In vitro, DIO (2, 6, and 8 µM) alleviates cell injury and apoptosis effectively in human embryonic kidney (HEK293) cells. DIO realizes its protective function via the regulation of endoplasmic reticulum (ER) stress and mitochondrial apoptosis pathway. Blockage of ER stress by 4-phenylbutyric acid (4-PBA), a specific ER stress antagonist, inhibits mitochondrial apoptosis, suggesting a connection between mitochondrial apoptosis and ER stress. Furthermore, the study demonstrates that the maintenance of Ca2+ homeostasis and Bcl2 expression, two main targets of ER stress, contributes to the protection role of DIO on mitochondrial-dependent apoptosis. In addition, DIO relieves the impairment of oxidative phosphorylation.

CONCLUSION

This study demonstrates that DIO exerts protective effect against kidney injury, mitochondrial dysfunction, and apoptosis through the inhibition of ER stress and the further maintenance of Ca2+ homeostasis and Bcl2 expression.

LKB1/AMPKα signaling pathway and mitochondrial fission/fusion dynamics regulate apoptosis induced by 3-chlorpropane-1,2-diol in HEK293 cells

Mitochondrial dynamics and bioenergetics are considered play pivotal roles in the maintenance of mitochondrial function and cell viability. During the widely distributed food contaminant 3-chlorpropane-1,2-diol (3-MCPD) induced nephrotoxicity, mitochondrial morphology and function were impaired, but the specific mechanism responsible for the process has not been fully elucidated. In the present study, using an in vitro human embryonic kidney 293 (HEK293) cell culture model, the role of LKB1/AMPK pathway and mitochondrial fission and fusion dynamics in 3-MCPD-induced cell apoptosis was investigated by using the AMPK inhibitor dorsomorphin and mitochondrial division inhibitor 1 (Mdivi-1), respectively. The results revealed that 3-MCPD significantly decreased the ATP levels, activated the energy-sensing regulator AMPKα and its upstream protein kinase LKB1, disrupted mitochondrial dynamics equilibrium characterized by promoting division and inhibiting fusion, thus inducing cell apoptosis. Notably, suppression of AMPK by dorsomorphin mitigated 3-MCPD-induced cytotoxicity through improvement of the function and dynamics of mitochondria and alleviated apoptosis via the mitochondria-dependent pathway. Moreover, inhibition of mitochondrial fission by Mdivi-1 protected against apoptosis induced by 3-MCPD. Taken together, these results suggest that 3-MCPD triggers apoptosis through activation of LKB1/AMPKα signaling pathway and regulation of mitochondrial fission and fusion dynamics in HEK293 cells.

Drp1-mediated mitochondrial fission induced autophagy attenuates cell apoptosis caused by 3-chlorpropane-1,2-diol in HEK293 cells

3-chlorpropane-1,2-diol (3-MCPD) is a heat-induced food process contaminant that threatens human health. As the primary target organ, the morphological and functional impairment of kidney and the related mechanism such as apoptosis and mitochondrial dysfunction were observed. However, the precise molecular mechanism remains largely unclear. This study aimed to explore the important role of mitochondrial fission and autophagy in the 3-MCPD-caused apoptosis of human embryonic kidney 293 (HEK293) cells. The results showed that blockage of dynamin-related protein-1 (Drp1) by mitochondrial division inhibitor 1 (Mdivi-1, 15 μM) apparently restored 3-MCPD-induced mitochondrial dysfunction, accompanied by prevented the collapse of mitochondrial membrane potential and ATP depletion, and suppressed the occurrence of autophagy. Induction of autophagy occurred following 2.5-10 mM 3-MCPD treatment for 24 h via AMPK mediated mTOR signaling pathway. Meanwhile, enhancement of autophagy by pretreatment with rapamycin (1 nM) alleviated the loss of cell viability and apoptosis induced by 3-MCPD whereas suppression of autophagy by 3-methyladenine (1 mM) further accelerated apoptosis, which was modulated through the mitochondria-dependent apoptotic pathway. Taking together, this study provides novel insights into the 3-MCPD-induced apoptosis in HEK293 cells and reveals that autophagy has potential as an effective intervention strategy for the treatment of 3-MCPD-induced nephrotoxicity.

Effects of 2-MCPD on oxidative stress in different organs of male mice

2-Monochloropropane-1,3-diol (2-MCPD) and its isomer 3-monochloropropane-1,2-diol (3-MCPD) are widespread food contaminants. 3-MCPD has been classified as a non-genotoxic carcinogen, whereas very limited toxicological data are available for 2-MCPD. Animal studies indicate that heart and skeletal muscle are target organs of 2-MCPD. Oxidative stress may play a role in this process, and the potential of 3-MCPD to induce oxidative stress in vivo has already been demonstrated. To investigate the potential of 2-MCPD to induce oxidative stress in vivo, a 28-day oral feeding study in male HOTT reporter mice was conducted. This mouse model allows monitoring substance-induced oxidative stress in various target organs on the basis of Hmox1 promoter activation. Repeated daily doses of up to 100 mg 2-MCPD/kg body weight did not result in substantial toxicity. Furthermore, the highest dose of 2-MCPD had only minor effects on oxidative stress in kidney and testes, whereas brain, heart and skeletal muscle were not affected. Additionally, 2-MCPD caused only mild changes in the expression of Nrf2-dependent genes and only slightly affected the redox status of the redox-sensor protein DJ-1. Thus, the data indicate that 2-MCPD, in contrast to its isomer 3-MCPD, does not lead to a considerable induction of oxidative stress in male mice.