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Starek-Świechowicz B, Szymczak W, Budziszewska B, Starek A. Testicular effect of a mixture of 2-methoxyethanol and 2-ethoxyethanol in rats. Pharmacol Rep 2014; 67:289-93. [PMID: 25712652 DOI: 10.1016/j.pharep.2014.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND 2-Methoxyethanol (ME) and 2-ethoxyethanol (EE) represent a large group of chemicals which are used separately or as mixtures. These compounds exert multidirectional toxic effects. The present studies aimed to demonstrate the effects of ME and EE alone and their mixture on the reproductive organs in the rats. METHODS Male Wistar rats were treated subcutaneously with ME and EE alone (1.25-5.0mM/kg/day) or with their mixture (1:1) for 4 weeks. After completion of the experiment, the testes, epididymides, and prostate were weighed. In post-mitochondrial supernatant of the testes, the level of total protein, non-protein and protein sulfhydryl groups, malondialdehyde, total antioxidant status, and glutathione peroxidase and glutathione reductase activities were determined. RESULTS Exposure to ME alone resulted in a dose-dependent decrease in the organ weights, the total protein, non-protein and protein sulfhydryl groups. EE alone led to less marked alterations. Co-exposure to ME and EE caused alterations similar as in the rats treated with ME alone. CONCLUSIONS Marked testicular atrophy, decrease in epididymis and prostate weights are predominant effects of the repeated exposure to relatively low doses of ME and EE. A decrease in the total protein level, and protein sulfhydryl groups may be responsible for testicular atrophy. A significant depletion of non-protein sulfhydryl groups and occasionally elevated glutathione peroxidase activity may indicate that ME and EE resulted in disturbances of pro-oxidant/antioxidant balance. The study suggests that testicular toxicity in male rats co-exposed to ME and EE is mainly caused by the former compound.
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Affiliation(s)
- Beata Starek-Świechowicz
- Department of Biochemical Toxicology, Chair of Toxicology, Medical College, Jagiellonian University, Kraków, Poland.
| | | | - Bogusława Budziszewska
- Department of Biochemical Toxicology, Chair of Toxicology, Medical College, Jagiellonian University, Kraków, Poland; Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Andrzej Starek
- Department of Biochemical Toxicology, Chair of Toxicology, Medical College, Jagiellonian University, Kraków, Poland
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HARYONO AGUS, SURJONO TIENWIATI, SUTASURYA LIENALINA, SUDARWATI SRI. Methoxyacetic Acid Induced Apoptosis on the Forelimb Bud of Swiss Webster Mice. HAYATI JOURNAL OF BIOSCIENCES 2011. [DOI: 10.4308/hjb.18.1.33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Clarke DO. Pharmacokinetic Studies in Developmental Toxicology: Practical Considerations and Approaches. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15376519309068441] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Scofield EH, Henderson WM, Funk AB, Anderson GL, Smith MA. Diethylene glycol monomethyl ether, ethylene glycol monomethyl ether and the metabolite, 2-methoxyacetic acid affect in vitro chondrogenesis. Reprod Toxicol 2006; 22:718-24. [PMID: 16829022 DOI: 10.1016/j.reprotox.2006.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 05/04/2006] [Accepted: 05/11/2006] [Indexed: 10/24/2022]
Abstract
Diethylene glycol monomethyl ether (DEGME), ethylene glycol monomethyl ether (EGME) and their common metabolite, methoxyacetic acid (MAA) have been associated with adverse reproductive effects. The objective of this research is to investigate the effects of DEGME, EGME and MAA on in vitro chondrogenesis and the mechanisms by which these effects occur. Micromass cultures were exposed to DEGME, EGME or MAA for 5 days and proteoglycan abundance and cell proliferation determined. Longer-term 9- and 14-day cultures were exposed to MAA and apoptosis analyzed. All three chemicals decreased proteoglycan abundance and cell proliferation at the highest dose tested (100 microL/mL). However, only MAA showed a dose-dependent effect for both parameters at 0.01, 10, and 100 microL/mL. Furthermore, micromass cultures show an increase in apoptotic cells which when treated with MAA suggest that cell death could result from induced apoptosis. These results suggest that effects of DEGME and EGME are the result of generalized toxicity, but their metabolite MAA induces mitochondrial-mediated apoptosis during in vitro chondrogenesis.
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Affiliation(s)
- Emily Hanson Scofield
- University of Georgia, Department of Environmental Health Science, Athens, GA 30602-2102, USA
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Welsch F. The mechanism of ethylene glycol ether reproductive and developmental toxicity and evidence for adverse effects in humans. Toxicol Lett 2005; 156:13-28. [PMID: 15705484 DOI: 10.1016/j.toxlet.2003.08.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Numerous experimental studies have established that only a few among the large family of ethylene glycol ethers (EGEs) elicit toxicity on reproduction in either gender. Notable are the monomethyl (EGME) and monoethyl (EGEE) ethers and their respective acetate esters whose production volumes have dramatically declined. Oxidation to the respective monoalkoxy acids is a prerequisite for toxicity. The most potent EGE reproductive toxicant is EGME (via 2-methoxyacetic acid; MAA), which elicits developmental phase-specific insults on either conceptus or on testes. Toxicity at either target site is markedly attenuated by simple physiological compounds such as acetate, formate, glycine, D-glucose and serine. Lack of solid EGME occupational exposure data and the need to improve the scientific foundations for animal data extrapolations, prompted the development of physiologically based pharmacokinetic (PBPK) models for pregnancy application. Interspecies (mouse-rat) and different exposure routes (including inhalation) were experimentally validated. Such PBPK models were then extrapolated to potential occupational exposures, using rather limited human MAA pharmacokinetic data. PBPK model predictions of human blood levels upon simulated inhalation exposure to the 5 ppm threshold limit value (TLV) for 8 h were approximately 60 microM were well below those causing adverse effects in pregnant mice or rats. This conclusion concurs with the lack of objective analytical chemistry data for EGME/MAA in occupational settings, regardless of the potential route of exposure. There are no exposure data that can be linked in a cause-and-effect association to adverse human reproductive outcomes.
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Affiliation(s)
- Frank Welsch
- Orbitox, International Toxicology Consultants, 1 Caliente Place, Santa Fe, NM 87508, USA.
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Choi HS, Park JH, Song JS, Cho YB. Determination of urinary metabolites of alkyl cellosolves by solid phase extraction and GC/FID. J Occup Health 2004; 46:260-5. [PMID: 15308824 DOI: 10.1539/joh.46.260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Alkyl cellosolves include ethylene glycol monomethylether, ethylene glycol monoethylether, ethylene glycol monobuthylether. And their urine metabolites are methoxyacetic acid, ethoxyacetic acid and butoxyacetic acid. The current analytical method for urinary alkoxyacetic acid is liquid-liquid phase extraction. But the liquid-liquid phase extraction method needs a more complex pre-treatment process and has a low recovery rate. We determined the appropriate extraction solvent and its flow rate. We also evaluated the non-absorptive rate and recovery rate according to particle size. Finally we developed a convenient solid phase extraction method for the analysis of urine cellosolve metabolites. As a result, the recovery rates for methoxyacetic acid, ethoxyacetic acid and butoxyacetic acid were 100.4 +/- 1.6%, 100.2 +/- 1.8% and 100.7 +/- 10.0% respectively, when acetone was used as the extraction solution. The most appropriate flow rate was 0.1 ml/min. At a particle size of 140-200 mesh, non-absorption percentages for methoxyacetic acid, ethoxyacetic acid, butoxyacetic acid were 3.2 +/- 0.3%, 1.0 +/- 0.1% and 1.1 +/- 0.1%, and the recovery rates according to particle size were similar. Further evaluation of the recovery rate and non-absorptive rate according to the mini column shape, stationary phase and recovery rate with various extracting solutions is required.
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Affiliation(s)
- Hong Soon Choi
- Department of Environment Engineering, Yonsei University, South Korea
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Abstract
Ethylene glycol monomethyl ether (EGME) and its acetate ester (EGMEA) are highly flammable, colorless, moderately volatile liquids with very good solubility properties. They are used in paints, lacquers, stains, inks and surface coatings, silk-screen printing, photographic and photo lithographic processes, for example, in the semiconductor industry, textile and leather finishing, production of food-contact plastics, and as an antiicing additive in hydraulic fluids and jet fuel. EGME and EGMEA are efficiently absorbed by inhalation as well as via dermal penetration. Dermal absorption may contribute substantially to the total uptake following skin contact with liquids or vapours containing EGME or EGMEA. EGMEA is rapidly converted to EGME in the body and the two substances are equally toxic in animals. Therefore, the two substances should be considered as equally hazardous to man. Effects on peripheral blood, testes, and sperm have been reported at occupational exposure levels ranging between 0.4 and 10 ppm EGME in air, and with additional, possibly substantial, dermal exposure. Severe malformations and disturbed hematopoiesis have been linked with exposure to EGME and EGMEA at unknown, probably high, levels. Embryonic deaths in monkeys and impaired spermatogenesis in rabbits have been reported after daily oral doses of 12 and 25 mg per kg body weight, respectively. In several studies, increased frequency of spontaneous abortions, disturbed menstrual cycle, and subfertility have been demonstrated in women working in the semiconductor industry. The contribution of EGME in relation to other exposure factors in the semiconductor industry is unclear.
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Affiliation(s)
- G Johanson
- Program for Toxicology and Risk Assessment, National Institute for Working Life, Stockholm, Sweden
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Sleet RB, Ross WP. Serine-enhanced restoration of 2-methoxyethanol-induced dysmorphogenesis in the rat embryo and near-term fetus. Toxicol Appl Pharmacol 1997; 145:415-24. [PMID: 9266816 DOI: 10.1006/taap.1997.8202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Effects of serine on restorative growth were characterized by comparing embryo/fetal responses after maternal exposure to 2-methoxyethanol (ME) and ME + serine by gavage on gestation day (gd) 13, a day of heightened limb sensitivity. Paws (gd 20) and limb buds (gd 15) were examined after ME alone at 50, 100, and 250 mg/kg, and after ME (either 100 or 250 mg ME/kg) + serine (1734 mg serine/kg) administered within minutes (0 hr) to 24 hr after ME. Paw development was not altered after ME at 100 mg/kg, but was highly sensitive to 250 mg ME/kg with all fetuses and litters exhibiting defects (ectrodactyly, syndactyly, and short digit) in the preaxial region. In contrast, the limb bud displayed dose-related incidences of abnormalities after maternal treatment with the low and high levels of ME. The condensing (precartilaginous, pentadactyl pattern) and noncondensing (undifferentiated mesenchymal cells) regions exhibited changes in their size, number, and location. Serine administration after 250 mg ME/kg was effective in reducing the occurrence of paw dysmorphogenesis with its protection potency inversely related to its delay of administration (i.e., 0% paw defect incidence after 0-hr delay, 25% after 4-hr delay, 41-45% after 8- and 12-hr delays, and 76% after 24-hr delay). The occurrences of limb bud pattern disturbances produced by ME were also markedly decreased by serine cotreatment. Higher incidences of embryonic defects versus those of fetal defects demonstrate that restorative growth followed ME exposure. Serine attenuation of ME teratogenicity appears to emanate from enhanced restorative growth so that tissue damage, which otherwise would be expressed as a defect at parturition, is repaired and replaced to resume development of the limb toward its normal structure.
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Affiliation(s)
- R B Sleet
- Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194, USA
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Clarke DO, Duignan JM, Welsch F. 2-Methoxyacetic acid dosimetry-teratogenicity relationships in CD-1 mice exposed to 2-methoxyethanol. Toxicol Appl Pharmacol 1992; 114:77-87. [PMID: 1585375 DOI: 10.1016/0041-008x(92)90099-e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The teratogen 2-methoxyethanol (2-ME), an industrial solvent, was administered to pregnant CD-1 mice either as a single subcutaneous (sc) bolus dose (100-250 mg/kg) or via constant-rate infusion from sc implanted osmotic minipumps (34.7 or 69.4 mg/kg/hr for up to 12 hr) on gestation Day 11, when embryonic paw development is maximally sensitive to perturbation by this agent. The sc entry route most closely reflects likely human exposures via dermal penetration, while bolus and constant-rate infusion administrations were contrasted to mimic potential occupational exposure scenarios. The pharmacokinetic profiles of 2-methoxyacetic acid (2-MAA), the proximate toxic metabolite of 2-ME, were quantitated, generating peak concentration (Cmax) and total 2-MAA exposure values (24-hr area under the concentration-time curve; AUC) in the maternal plasma, extraembryonic fluid, and embryo. The total 2-ME dose (mg/kg) required to achieve similar 2-MAA levels (Cmax or AUC) in these compartments was 2- to 3-fold higher by constant-rate infusion than by bolus injection; therefore, no simple association existed between 2-MAA levels and the total 2-ME dose, when the dose rate was not considered. Similarly, there was no good correlation between the combined total 2-ME doses and the fetal malformation rate, although clear dose-response patterns for paw malformations were observed in litters and fetuses for each individual dosing regimen. However, the combined 2-MAA pharmacokinetic data from each of the dosing regimens demonstrated that during the phase of maximum susceptibility of paw morphogenesis to disruption by 2-MAA (from gd 11 to gd 11.5), a strong linear correlation existed between fetal malformation incidence and 2-MAA AUC levels in either maternal plasma or embryonic compartments (linear correlation coefficient, r2 0.91-0.92). The correlation with Cmax was less favorable (r2 0.74-0.81) over the dose range studied. In a further experiment designed to investigate the importance of AUC vs Cmax regarding 2-ME teratogenicity, infusion of 2-ME (34.7 mg/kg/hr for 8 hr) beginning 2.5 hr after bolus loading (175 mg/kg) provided an increased 24-hr 2-MAA AUC without increased Cmax. This resulted in greater than 70% of the fetuses having various digit malformations (micro-, syn-, ectro-, and polydactyly), compared to only 32-35% of fetuses with mostly stunted digits when either dose was applied singularly. These data support total 2-MAA exposure (AUC levels), rather than peak 2-MAA concentrations, as the principle determinant of teratogenesis following exposure to 2-ME.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- D O Clarke
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709
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