Comparative study on estrogen receptor alpha dimerization and transcriptional activity of parabens.

Parabens are used as preservatives in various household products, including oral products, cosmetics, and hair/body washes. In recent years, the widespread use of parabens has raised concerns due to the potential health risks associated with their estrogenic effects. In the present study, we evaluated and compared the estrogenic activity of parabens using two cell-based in vitro tests: (1) bioluminescence resonance energy transfer (BRET)-based estrogen receptor alpha (ERα) dimerization using HEK293 cells that were stably transfected with ERα-fused NanoLuc luciferase (Nluc) and HaloTag (HT) expression vector, and (2) stably transfected transcriptional activation (STTA) assays using ERα-HeLa9903 cells. The following parabens were tested using the BRET-based ERα dimerization assay and showed estrogenic activity (PC20 values): methyl paraben (MP, 5.98 × 10-5 M), ethyl paraben (EP, 3.29 × 10-5 M), propylparaben (PP, 3.09 × 10-5 M), butyl paraben (BP, 2.58 × 10-5 M), isopropyl paraben (IsoPP, 1.37 × 10-5 M), and isobutyl paraben (IsoBP, 1.43 × 10-5 M). Except MP, all other parabens tested using the STTA assay also showed estrogenic activity: EP, 7.57 × 10-6 M; PP, 1.18 × 10-6 M; BP, 3.02 × 10-7 M; IsoPP, 3.58 × 10-7 M; and IsoBP, 1.80 × 10-7 M. Overall, EP, PP, BP, IsoPP, and IsoBP tested positive for estrogenic activity using both assays. These findings demonstrate that most parabens, albeit not all, induce ERα dimerization and possess estrogenic activity.

Comprehensive assessment of the estrogenic activity of resin composites.

Resin-based dental composites have been developed to restore decayed teeth or modify tooth color due to their excellent physical and chemical properties. Such composites may have intrinsic toxicity due to components released into the mouth during the early stage of polymerization, and afterward as a result of erosion or material decomposition. In addition, resin-based dental composites have potential environmental pollutant by elution of monomers and degradation. Since certain monomers of resin matrices are synthesized from bisphenol A (BPA), which acts as an estrogenic endocrine disruptor, these resin matrices may have estrogenic activity. Therefore, the estrogenic endocrine-disrupting activity of various dental composites should be evaluated. In this study, we evaluated the estrogenic endocrine-disrupting activity of 10 resin composites by using a BRET-based estrogen receptor (ER)α and ERß dimerization assays and ER transactivation assay. BPA, BisDMA, BisGMA, BisEMA, TEGDMA, HMBP, and DMPA mediated ERα dimerization, and BPA, BisDMA, and DMPA also mediated ERß dimerization. Except for UDMA and CQ, all the compounds were identified as estrogen agonists or antagonists. In-depth information for the safe use of dental composites was acquired, and it was confirmed how the component of dental composites acts in the ER signaling pathway. Further studies on the low-dose and long-term release of these compounds are needed to ensure the safe use of these resin-based dental composites.

Effects of gypenoside L-containing Gynostemma pentaphyllum extract on fatigue and physical performance: A double-blind, placebo-controlled, randomized trial.

This study was conducted to investigate the effect of Gynostemma pentaphyllum extract containing gypenoside L (GPE) on improving the cognitive aspects of fatigue and performance of the motor system. One hundred healthy Korean adults aged 19-60 years were randomized to the treatment (GPE for 12 weeks) and control groups, and efficacy and safety-related parameters were compared between the two groups. Maximal oxygen consumption (VO2 max) and O2 pulse were significantly higher in the treatment group than in the control group (p = 0.007 and p = 0.047, respectively). After 12 weeks, the treatment group showed significant changes such as decreases in the levels of free fatty acids (p = 0.042). In addition, there were significant differences in the rating of perceived exertion (RPE) (p < 0.05) and value of temporal fatigue between the treatment and control groups on the multidimensional fatigue scale (p < 0.05). Moreover, the level of endothelial nitric oxide synthase (eNOS) in the blood was significantly higher in the treatment group than in the control group (p = 0.047). In summary, oral administration of GPE has a positive effect on resistance to exercise-induced physical and mental fatigue.

Comprehensive analysis of cellular estrogen signaling in representative estrogen receptor ligands.

The estrogen receptor (ER)-mediated signaling pathway in physiological and biochemical aspects is very important in the environment, including food. The physiological action of estrogen is mediated by ER alpha (ERα) and beta (ERß), whose physiological action on estrogenic substances is complex because of the relatively low ligand-binding domain (LBD) similarity of the two ERs. In this study, the comprehensive activity of representative ER ligands was evaluated by using BRET-based ERα and ERß dimerization and ER transactivation assays to differentiate the specific binding and function of ERα and ERß from 12 representative natural and synthetic estrogenic substances. Results revealed that 11 chemicals mediated receptor ERα and ERß dimerization, 7 out of 12 chemicals were confirmed to be estrogen agonists, and 5 chemicals were antagonistic. Overall, this study demonstrated consistency between BRET dimerization and transactivation responses, supporting potential supplementary application of mechanism-based BRET assays as high-throughput screening methods for evaluation of potential endocrine-disrupting activity of environmental agents. This study also provided information about receptor specificity of ligand-mediated estrogenic activity via dimerization assays and elucidated cellular estrogen signaling pathways.

Human cell-based estrogen receptor beta dimerization assay.

Estrogen is not only responsible for important functions in the human body, such as cell growth, reproduction, differentiation, and development, but it is also deeply related to pathological processes, such as cancer, metabolic and cardiovascular diseases, and neurodegeneration. Estrogens and other estrogenic compounds have transcriptional activities through binding with the estrogen receptor (ER) to induce ER dimerization. The two estrogen receptor subtypes, estrogen receptor alpha (ERα) and estrogen receptor beta (ERß), show structural differences and have different expression ratios in specific cells and tissues. Currently, the methods for confirming the estrogenic properties of compounds are the binding (Test guideline no. 493) and transactivation (Test guideline no. 455) assays provided by the Organization for Economic Co-operation and Development (OECD). In a previous study, we developed an ERα dimerization assay based on the bioluminescence resonance energy transfer (BRET) system, but there are currently no available tests that can confirm the effect of estrogenic compounds on ERß. Therefore, in this study, we developed a BRET-based ERß dimerization assay to confirm the estrogenic prosperities of compounds. The BRET-based ERß dimerization assay was verified using nine representative ER ligands and the results were compared with the dimerization activity of ERα. In conclusion, our BRET-based ERß dimerization assay can provide information on the ERß dimerization potential of estrogenic compounds.

Effect of Annealing Temperature on the Structural and Electrochemical Properties of Hydrothermally Synthesized NiCo2O4 Electrodes.

In this study, a porous Ni-foam support was employed to enhance the capacitance of nickel cobaltite (NiCo2O4) electrodes designed for supercapacitors. The hydrothermal synthesis method was employed to grow NiCo2O4 as an active material on Ni-foam. The NiCo2O4 sample derived from hydrothermal synthesis underwent subsequent post-heat treatment at temperatures of 250 °C, 300 °C, and 350 °C. Thermogravimetric analysis of the NiCo2O4 showed that weight loss due to water evaporation occurs after 100 °C and enters the stabilization phase at temperatures above 400 °C. The XRD pattern indicated that NiCo2O4 grew into a spinel structure, and the TEM results demonstrated that the diffraction spots (DSs) on the (111) plane of the sample annealed at 350 °C were more pronounced than those of other samples. The specific capacitance of the NiCo2O4 electrodes exhibited a decrease with increasing current density across all samples, irrespective of the annealing temperature. The electrode annealed at 350 °C recorded the highest specific capacitance value. However, the capacity retention rate of the NiCo2O4 electrode revealed a deteriorating trend, declining to 88% at 250 °C, 75% at 300 °C, and 63% at 350 °C, as the annealing temperature increased.

Murine blastocysts generated by in vitro fertilization show increased Warburg metabolism and altered lactate production.

In vitro fertilization (IVF) has resulted in the birth of over 8 million children. Although most IVF-conceived children are healthy, several studies suggest an increased risk of altered growth rate, cardiovascular dysfunction, and glucose intolerance in this population compared to naturally conceived children. However, a clear understanding of how embryonic metabolism is affected by culture condition and how embryos reprogram their metabolism is unknown. Here, we studied oxidative stress and metabolic alteration in blastocysts conceived by natural mating or by IVF and cultured in physiologic (5%) or atmospheric (20%) oxygen. We found that IVF-generated blastocysts manifest increased reactive oxygen species, oxidative damage to DNA/lipid/proteins, and reduction in glutathione. Metabolic analysis revealed IVF-generated blastocysts display decreased mitochondria respiration and increased glycolytic activity suggestive of enhanced Warburg metabolism. These findings were corroborated by altered intracellular and extracellular pH and increased intracellular lactate levels in IVF-generated embryos. Comprehensive proteomic analysis and targeted immunofluorescence showed reduction of lactate dehydrogenase-B and monocarboxylate transporter 1, enzymes involved in lactate metabolism. Importantly, these enzymes remained downregulated in the tissues of adult IVF-conceived mice, suggesting that metabolic alterations in IVF-generated embryos may result in alteration in lactate metabolism. These findings suggest that alterations in lactate metabolism are a likely mechanism involved in genomic reprogramming and could be involved in the developmental origin of health and disease.

Generation of a Dystrophin Mutant in Dog by Nuclear Transfer Using CRISPR/Cas9-Mediated Somatic Cells: A Preliminary Study.

Dystrophinopathy is caused by mutations in the dystrophin gene, which lead to progressive muscle degeneration, necrosis, and finally, death. Recently, golden retrievers have been suggested as a useful animal model for studying human dystrophinopathy, but the model has limitations due to difficulty in maintaining the genetic background using conventional breeding. In this study, we successfully generated a dystrophin mutant dog using the CRISPR/Cas9 system and somatic cell nuclear transfer. The dystrophin mutant dog displayed phenotypes such as elevated serum creatine kinase, dystrophin deficiency, skeletal muscle defects, an abnormal electrocardiogram, and avoidance of ambulation. These results indicate that donor cells with CRISPR/Cas9 for a specific gene combined with the somatic cell nuclear transfer technique can efficiently produce a dystrophin mutant dog, which will help in the successful development of gene therapy drugs for dogs and humans.

Possibility of Pseudo-Obstruction in Lacrimal Canalicular Obstruction Diagnosed with Dacryocystography.

INTRODUCTION: Endoscopic dacryocystorhinostomy (DCR) is the treatment of choice for patients with lacrimal drainage system obstruction. Dacryocystography (DCG) is one of the most common preoperative studies and considered as a useful test demonstrating the anatomy of lacrimal drainage systems. OBJECTIVE: This study was designed to evaluate the diagnostic efficacy of DCG for canalicular obstruction and to compare surgical outcomes between true-obstruction versus pseudo-obstruction diagnosed with DCG. METHODS: A retrospective study was performed on 45 consecutive patients with lacrimal canalicular obstruction who had underwent endoscopic DCR with silicone tube insertion from January 2009 to December 2014 at a single tertiary hospital. A review of medical records included demographic data, preoperative symptoms and signs, results of intraoperative canalicular probing, and surgical outcomes including the postoperative symptom improvement and endoscopic finding. RESULTS: Of 45 patients, 34 patients (75.6%) had true-canalicular obstructions and 11 patients (24.4%) had pseudo-canalicular obstructions. The success rate of endoscopic DCR was 50% (17 of 34) in cases with true-canalicular obstruction while 90.9% (10 of 11) in pseudo-canalicular obstruction (p value <0.05). No intraoperative or postoperative complications including sinusitis or synechia were found. CONCLUSIONS: About a quarter of lacrimal canalicular obstruction cases diagnosed with DCG seem to be pseudo-obstruction. The success rate of endoscopic DCR in pseudo-canalicular obstruction is similar to that of saccal and nasolacrimal ductal obstruction.

DNA methylation profile of liver of mice conceived by in vitro fertilization.

Offspring generated by in vitro fertilization (IVF) are believed to be healthy but display a possible predisposition to chronic diseases, like hypertension and glucose intolerance. Since epigenetic changes are believed to underlie such phenotype, this study aimed at describing global DNA methylation changes in the liver of adult mice generated by natural mating (FB group) or by IVF. Embryos were generated by IVF or natural mating. At 30 weeks of age, mice were sacrificed. The liver was removed, and global DNA methylation was assessed using whole-genome bisulfite sequencing (WGBS). Genomic Regions for Enrichment Analysis Tool (GREAT) and G:Profilerß were used to identify differentially methylated regions (DMRs) and for functional enrichment analysis. Overrepresented gene ontology terms were summarized with REVIGO, while canonical pathways (CPs) were identified with Ingenuity® Pathway Analysis. Overall, 2692 DMRs (4.91%) were different between the groups. The majority of DMRs (84.92%) were hypomethylated in the IVF group. Surprisingly, only 0.16% of CpG islands were differentially methylated and only a few DMRs were located on known gene promoters (n = 283) or enhancers (n = 190). Notably, the long-interspersed element (LINE), short-interspersed element (SINE), and long terminal repeat (LTR1) transposable elements showed reduced methylation (P < 0.05) in IVF livers. Cellular metabolic process, hepatic fibrosis, and insulin receptor signaling were some of the principal biological processes and CPs modified by IVF. In summary, IVF modifies the DNA methylation signature in the adult liver, resulting in hypomethylation of genes involved in metabolism and gene transcription regulation. These findings may shed light on the mechanisms underlying the developmental origin of health and disease.

An In vitro dimerization assay for the adverse outcome pathway approach in risk assessment of human estrogen receptor α-mediated endocrine-disrupting chemicals.

The adverse outcome pathway (AOP) has been recently proposed as an effective framework for chemical risk assessment. The AOP framework offers the advantage of effectively integrating individual in vitro studies and in silico prediction models. Thus, the development of an effective testing method to measure key events caused by chemicals is essential for chemical risk assessment through a fully developed AOP framework. We developed a human cell-based estrogen receptor α (ERα) dimerization assay using the bioluminescence resonance energy transfer (BRET) technique and evaluated the ERα dimerization activities of 72 chemicals. Fifty-one chemicals were identified to mediate dimerization of ERα, and the BRET-based ERα dimerization assay could effectively measure the events that mediated dimerization of ERα by the estrogenic chemicals. These results were compared with the results of pre-existing assay to determine whether the BRET-based ERα dimerization assay could be employed as an in vitro test method to provide scientific information for explaining key events as a part of the AOP framework. Consequently, we propose that the BRET-based ERα dimerization assay is suitable for measuring the chemical-mediated dimerization of ERα, a key event in the AOP framework for cellular-level risk assessment of estrogenic chemicals.

Comparative study of estrogenic activities of phytoestrogens using OECD in vitro and in vivo testing methods.

With growing scientific interest in phytoestrogens, a number of studies have investigated the estrogenic potential of phytoestrogens in a wide variety of assay systems. However, evaluations of individual phytoestrogens with different assay systems make it difficult for predicting their relative estrogenic potency. The objective of this study was to compare estrogenic properties of fifteen known phytoestrogens using an estrogen receptor-α (ER-α) dimerization assay and Organization for Economic Cooperation and Development (OECD) standardized methods including in vitro estrogen receptor (ER) transactivation assay using VM7Luc4E2 cells and in vivo uterotrophic assay using an immature rat model. Human ER-α dimerization assay showed positive responses of eight test compounds and negative responses of seven compounds. These results were consistently found in luciferase reporter assay results for evaluating ER transactivation ability. Seven test compounds exhibiting relatively higher in vitro estrogenic activities were subjected to uterotrophic bioassays. Significant increases in uterine weights were only found after treatments with biochanin A, 8-prenylnaringenin, and coumestrol. Importantly, their uterotrophic effects were lost when animals were co-treated with antagonist of ER, indicating their ER-dependent effects in the uterus. In addition, analysis of estrogen responsive genes revealed that these phytoestrogens regulated uterine gene expressions differently compared to estrogens. Test methods used in this study provided a high consistency between in vitro and in vivo results. Thus, they could be used as effective screening tools for phytoestrogens, particularly focusing on their interactions with ER-α.

Mechanistic insight into human androgen receptor-mediated endocrine-disrupting potentials by a stable bioluminescence resonance energy transfer-based dimerization assay.

To develop a novel cell-based assay to evaluate the androgenic endocrine-disrupting properties of chemical substances, we established a method to detect ligand-mediated androgen receptor (AR) dimerization in stably transfected human cell lines using a bioluminescence resonance energy transfer (BRET) system. Using stably transfected human embryonic kidney (HEK-293) cells, the BRET-based AR dimerization assay was optimized as a novel test method and was validated using test chemicals recommended by the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM). The BRET-based AR dimerization assay showed high accuracy, sensitivity, and specificity for the detection of androgenic endocrine-disrupting chemicals (EDCs), and the assay protocol is adequate for practical use. This dimerization assay is based on ligand-mediated hormone receptor dimerization and can provide accurate information about androgenic endocrine-disrupting properties at the cellular level, complementing conventional binding and transactivation assays.

Role of Extracellular Vesicles in Compromising Cellular Resilience to Environmental Stressors.

Extracellular vesicles (EVs), like exosomes, are nanosized membrane-enveloped vesicles containing different bioactive cargo, such as proteins, lipids, mRNA, miRNA, and other small regulatory RNAs. Cell-derived EVs, including EVs originating from stem cells, may capture components from damaged cells or cells impacted by therapeutic treatments. Interestingly, EVs derived from stem cells can be preconditioned to produce and secrete EVs with different therapeutic properties, particularly with respect to heat-shock proteins and other molecular cargo contents. This behavior is consistent with stem cells that also respond differently to various microenvironments. Heat-shock proteins play roles in cellular protection and mediate cellular resistance to radiotherapy, chemotherapy, and heat shock. This review highlights the possible roles EVs play in mediating cellular plasticity and survival when exposed to different physical and chemical stressors, with a special focus on the respiratory distress due to the air pollution.

Development of a Human Estrogen Receptor Dimerization Assay for the Estrogenic Endocrine-Disrupting Chemicals Using Bioluminescence Resonance Energy Transfer.

Endocrine-disrupting chemicals (EDCs) are found in food and various other substances, including pesticides and plastics. EDCs are easily absorbed into the body and have the ability to mimic or block hormone function. The radioligand binding assay based on the estrogen receptors binding affinity is widely used to detect estrogenic EDCs but is limited to radioactive substances and requires specific conditions. As an alternative, we developed a human cell-based dimerization assay for detecting EDC-mediated ER-alpha (ERα) dimerization using bioluminescence resonance energy transfer (BRET). The resultant novel BRET-based on the ERα dimerization assay was used to identify the binding affinity of 17ß-estradiol (E2), 17α-estradiol, corticosterone, diethylhexyl phthalate, bisphenol A, and 4-nonylphenol with ERα by measuring the corresponding BRET signals. Consequently, the BRET signals from five chemicals except corticosterone showed a dose-dependent sigmoidal curve for ERα, and these chemicals were suggested as positive chemicals for ERα. In contrast, corticosterone, which induced a BRET signal comparable to that of the vehicle control, was suggested as a negative chemical for ERα. Therefore, these results were consistent with the results of the existing binding assay for ERα and suggested that a novel BRET system can provide information about EDCs-mediated dimerization to ERα.

(-)-Epicatechin-Enriched Extract from Camellia sinensis Improves Regulation of Muscle Mass and Function: Results from a Randomized Controlled Trial.

Loss of skeletal muscle mass and function with age represents an important source of frailty and functional decline in the elderly. Antioxidants from botanical extracts have been shown to enhance the development, mass, and strength of skeletal muscle by influencing age-related cellular and molecular processes. Tannase-treated green tea extract contains high levels of the antioxidants (-)-epicatechin (EC) and gallic acid that may have therapeutic benefits for age-related muscle decline. The aim of this study was to investigate the effect of tannase-treated green tea extract on various muscle-related parameters, without concomitant exercise, in a single-center, randomized, double-blind, placebo-controlled study. Administration of tannase-treated green tea extract (600 mg/day) for 12 weeks significantly increased isokinetic flexor muscle and handgrip strength in the treatment group compared with those in the placebo (control) group. In addition, the control group showed a significant decrease in arm muscle mass after 12 weeks, whereas no significant change was observed in the treatment group. Blood serum levels of follistatin, myostatin, high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, IL-8, insulin-like growth factor-1 (IGF-1), and cortisol were analyzed, and the decrease in myostatin resulting from the administration of tannase-treated green tea extract was found to be related to the change in muscle mass and strength. In summary, oral administration of tannase-treated green tea extract containing antioxidants without concomitant exercise can improve muscle mass and strength and may have therapeutic benefits in age-related muscle function decline.

Comprehensive Proteomics Analysis of In Vitro Canine Oviductal Cell-Derived Extracellular Vesicles.

Dogs (Canis lupus familiaris) have unique and peculiar reproductive characteristics. While the interplay between in vitro oviductal cell-derived extracellular vesicles (OC-EVs) and cumulus-oocyte complexes in dogs has begun to be elucidated, no study has yet provided extensive information on the biological content and physiological function of OC-EVs and their role in canine oocyte development. Here, we aimed to provide the first comprehensive proteomic analysis of OC-EVs. We identified 398 proteins as present in all OC-EVs samples. The functional enrichment analysis using Gene Ontology terms and an Ingenuity Pathway Analysis revealed that the identified proteins were involved in several cellular metabolic processes, including translation, synthesis, expression, and protein metabolism. Notably, the proteins were also involved in critical canonical pathways with essential functions in oocyte and embryo development, such as ERK/MAPK, EIF2, PI3K/AKT, and mTOR signaling. These data would be an important resource for studying canine reproductive physiology and establishing a successful in vitro embryo production system in dogs.

Human Adipose-Derived Stem Cells' Paracrine Factors in Conditioned Medium Can Enhance Porcine Oocyte Maturation and Subsequent Embryo Development.

An essential requirement for the success of in vitro maturation (IVM) of the oocyte is to provide an optimal microenvironment similar to in vivo conditions. Recently, somatic cell-based coculture or supplementation of a conditioned medium during IVM has been performed to obtain better quality of oocytes, because they mimic the in vivo reproductive tract by secreting paracrine factors. In this study, human adipose-derived stem cells (ASC) and their conditioned medium (ASC-CM) were applied to IVM of porcine oocytes to evaluate the effectiveness of ASC on oocyte development and subsequent embryo development. In results, both ASC and ASC-CM positively influence on oocyte maturation and embryo development by regulating growth factor receptors (VEGF, FGFR, and IGFR), apoptosis (BCL2), cumulus expansion (PTGS2, HAS2, and TNFAIP6), and oocyte maturation-related genes (GDF9 and BMP15). In particular, the fluorescence intensity of GDF9 and BMP15 was markedly upregulated in the oocytes from the ASC-CM group. Furthermore, significantly high levels of growth factors/cytokine including VEGF, bFGF, IGF-1, IL-10, and EGF were observed in ASC-CM. Additionally, the ASC-CM showed active scavenging activity by reducing the ROS production in a culture medium. Consequently, for the first time, this study demonstrated the effect of human ASC-CM on porcine oocyte development and the alteration of mRNA transcript levels in cumulus-oocyte complexes.

Ovulation induction is associated with altered growth but with preservation of normal metabolic function in murine offspring.

OBJECTIVE: To study the effects of ovulation induction on mouse postnatal health, with a focus on growth pattern and glucose tolerance. To study the effect of ovulation induction on DNA methylation, we took advantage of the agouti viable yellow (Avy) mouse. DESIGN: Animal study. SETTING: University Setting. ANIMALS: Agouti viable yellow (Avy) mice on a C57BL/6 background. INTERVENTION(S): Avy female mice were either allowed to mate spontaneously (control group, C) or after superovulation with 5 IU of PMSG and hCG (ovulation induction group, OI). MAIN OUTCOME MEASURE(S): Birth parameters and postnatal growth of the offspring were followed up to 29 weeks of age. Body composition analysis was performed by EchoMRI; fasting insulin, intraperitoneal glucose tolerance tests, and glucose-stimulated insulin secretion by beta cells were assessed to study glucose metabolism. RESULT(S): Mice born to superovulated dams had lower survival rates, shorter anogenital distances, and shorter crown-rump lengths. Female mice generated by OI weighed less at birth, whereas male mice generated by OI had lower weight gain and had reduced lean mass. Glucose parameters, including islet functions, did not differ between the groups. No difference in agouti coat color was noted between the groups. CONCLUSION(S): Ovulation induction resulted in mice having increased morphometric differences at birth and male mice showing reduced weight gain but no difference in glucose tolerance or agouti coat color.

3-MCPD (3-monochloro-1,2-propanediol) inhibit myogenic differentiation in murine skeletal myoblasts.

3-Monochloro-1,2-propanediol (3-MCPD) is a chemical compound that is unintentionally produced during food processing such as acid hydrolysis. There has been reports regarding the role of this chemical compound in reproductive toxicity, as well as genotoxicity, neurotoxicity, and kidney toxicity. In this study, the in vitro muscle toxicity of 3-MCPD was assessed using C2C12 myoblast cells. The reduction in muscle regulatory factors (MRFs), which is related to muscle differentiation, was identified as significant with the increase concentration of 3-MCPD. Also, significantly decreased protein expression in mTOR and p70S6 kinase, which are the downstream targets of the pathway associated with muscle synthesis, was also confirmed. Therefore, the inhibitory effect of 3-MCPD on muscle differentiation is considered to be the cause of suppressing mTOR and p70S6 kinase expression. In conclusion, it was confirmed that 3-MCPD inhibits muscle differentiation in C2C12 myoblasts through suppressing the expression of several genetic factors involving muscle differentiation.