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Von Tungeln LS, Jacob CC, Olson GR, Gamboa da Costa G, Beland FA. Effect of urinary pH upon the renal toxicity of melamine and cyanuric acid. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, TOXICOLOGY AND CARCINOGENESIS 2021; 39:340-355. [PMID: 35895915 DOI: 10.1080/26896583.2021.1943270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In 2007, dietary exposure to "scrap melamine' resulted in the death of a large number of cats and dogs, which was attributed to the formation of melamine cyanurate crystals in their kidneys. In this study, we investigated if changes in urinary pH could diminish the renal toxicity associated with exposure to combinations of melamine and cyanuric acid. Female Sprague-Dawley rats were treated for three days with suspensions of melamine and cyanuric acid at doses that were expected to induce renal toxicity. Dosing was then discontinued and the rats were treated for seven days with drinking water solutions (i.e., ammonium chloride and sodium bicarbonate) that would alter urinary pH. The urinary pH of rats administered ammonium chloride drinking water decreased from pH 6.0-6.2 to pH 5.1-5.2. This was accompanied by a decrease in the incidence of melamine cyanurate crystals in the kidneys and a decrease in the incidence of renal lesions. These data suggest that acidification of urine may help overcome the renal toxicities associated with the formation of melamine cyanurate crystals in the kidney.
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Affiliation(s)
- Linda S Von Tungeln
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Cristina C Jacob
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Greg R Olson
- Toxicologic Pathology Associates, Jefferson, Arkansas, USA
| | - Gonçalo Gamboa da Costa
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas, USA
| | - Frederick A Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas, USA
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2
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Tebby C, Brochot C, Dorne JL, Beaudouin R. Investigating the interaction between melamine and cyanuric acid using a Physiologically-Based Toxicokinetic model in rainbow trout. Toxicol Appl Pharmacol 2019; 370:184-195. [PMID: 30922832 DOI: 10.1016/j.taap.2019.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/18/2019] [Accepted: 03/23/2019] [Indexed: 10/27/2022]
Abstract
Following outbreaks of feed and food adulterations with a melamine and cyanuric acid mixture in 2007 and melamine in 2008 respectively, the kinetics and toxicodynamics of the mixture have been investigated particularly in sensitive species such as the rainbow trout. Tissue concentrations and intensity of the adverse effect, melamine-cyanurate crystal formation in kidney, were reported in similar experimental conditions. Here, a recent PBTK model for rainbow trout has been applied to model the kinetics of both single compounds based on residue levels in tissues. Both PBTK models for the single compounds were combined and a model of crystal formation for the mixture melamine-cyanuric acid was also added to predict the intensity of crystal formation under the assumptions that crystals formed either in urine or in kidney tissue. Modelling the kinetics of melamine and cyanuric acid provided a better understanding and prediction of intensity of crystal formation in case of sequential exposures with varying intensity or co-exposure. This study demonstrates, for the first time, how fish PBTK models can play a key role in the understanding and prediction of toxicokinetics and toxicodynamics of mixtures. This study also illustrates how adverse effects may potentially occur even when the compounds are not administered together as a mixture.
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Affiliation(s)
- Cleo Tebby
- Institut National de l'Environnement Industriel et des Risques (INERIS), Models for Ecotoxicology and Toxicology Unit, Parc ALATA, BP2, 60550 Verneuil-en-Halatte, France
| | - Céline Brochot
- Institut National de l'Environnement Industriel et des Risques (INERIS), Models for Ecotoxicology and Toxicology Unit, Parc ALATA, BP2, 60550 Verneuil-en-Halatte, France
| | - Jean-Lou Dorne
- European Food Safety Authority (EFSA), Scientific Committee and Emerging Risks Unit, Via Carlo Magno 1A, 43126 Parma, Italy
| | - Rémy Beaudouin
- Institut National de l'Environnement Industriel et des Risques (INERIS), Models for Ecotoxicology and Toxicology Unit, Parc ALATA, BP2, 60550 Verneuil-en-Halatte, France; Institut National de l'Environnement Industriel et des Risques (INERIS), UMR-I 02 SEBIO, Parc ALATA, BP2, 60550 Verneuil-en-Halatte, France.
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Khalil SR, Awad A, Ali SA. Melamine and/or formaldehyde exposures affect steroidogenesis via alteration of StAR protein and testosterone synthetic enzyme expression in male mice. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 50:136-144. [PMID: 28183025 DOI: 10.1016/j.etap.2017.01.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
The reproductive effects of melamine and formaldehyde, either alone or in combination, on mature male Swiss mice were investigated. The animals were orally administered melamine (50mg/kg/day), formaldehyde (25mg/kg/day), a mixture of melamine and formaldehyde, or a vehicle control for 65 consecutive days. As a result, the deterioration of sperm characteristics and inhibition of testicular enzyme activity were observed in the melamine- and formaldehyde-exposed groups. In addition, testosterone and luteinizing hormone levels were significantly reduced in the melamine but not in the formaldehyde-exposed group, which correlated with down-regulation of transcription levels of steroidogenic-related genes. Histopathologically, both compounds caused lesions in the testes. However, the co-exposure reduced the induced alterations in spermatogenesis, steroidogenesis, and testicular architecture that were obviously observed in the melamine-exposed group. Consequently, we demonstrated that melamine exhibited more pronounced reproductive impact in comparison with formaldehyde. In addition, formaldehyde was able to substantially temper the melamine -induced reproductive toxic effect.
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Affiliation(s)
- Samah R Khalil
- Forensic Medicine and Toxicology Department, Faculty of Veterinary Medicine, Zagazig University, Egypt.
| | - Ashraf Awad
- Animal Wealth Development Department, Faculty of Veterinary Medicine, Zagazig University, Egypt
| | - Sozan A Ali
- Histology and Cytology Department, Faculty of Veterinary Medicine, Zagazig University, Egypt
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Studies using a porcine model: what insights into human calcium oxalate stone formation mechanisms has this model facilitated? Urolithiasis 2016; 45:109-125. [PMID: 27904915 DOI: 10.1007/s00240-016-0947-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/22/2016] [Indexed: 10/20/2022]
Abstract
Animal models are useful in the study of many human diseases. Our current understanding of the biological, physiological, and biochemical aspects of hyperoxaluria and calcium oxalate urolithiasis has been greatly informed by studies using animals. Recently, limitations in the extrapolation to humans of research results derived from laboratory rodents have been identified. The use in biomedical research of a variety of organisms, including large animals, is increasingly encouraged. The purpose of this article is to review the use of pigs in biomedical and stone research, to provide a rationale for using pigs in metabolic stone research, and to describe our 8-year experience in developing a porcine platform for studying hyperoxaluria and calcium oxalate urolithiasis. In this article, we share and review some of the highlights of our findings. We also report results from a recent feeding swine study that demonstrated oxalate-induced renal nephropathy. Finally, we offer ideas for future directions in urolithiasis research using swine.
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Lee IC, Ko JW, Park SH, Shin IS, Moon C, Kim SH, Kim YB, Kim JC. Melamine and cyanuric acid co-exposure causes renal dysfunction and structural damage via MAPKs and mitochondrial signaling. Food Chem Toxicol 2016; 96:254-62. [DOI: 10.1016/j.fct.2016.08.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/25/2016] [Accepted: 08/09/2016] [Indexed: 01/06/2023]
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6
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Tkachenko A, Clark J, Knutson N, Wallace B, Bomba M, Yacopucci M, Rhodes B, Nemser SM, Guag J, Reimschuessel R. Investigation of melamine and cyanuric acid deposition in pig tissues using LC-MS/MS methods. Food Chem Toxicol 2015; 80:310-318. [DOI: 10.1016/j.fct.2015.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 02/10/2015] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
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Liu H, Xue M, Wang J, Qiu J, Wu X, Zheng Y, Li J, Qin Y. Tissue deposition and residue depletion in rainbow trout following continuous voluntary feeding with various levels of melamine or a blend of melamine and cyanuric acid. Comp Biochem Physiol C Toxicol Pharmacol 2014; 166:51-8. [PMID: 25038476 DOI: 10.1016/j.cbpc.2014.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 07/08/2014] [Accepted: 07/08/2014] [Indexed: 11/15/2022]
Abstract
This study determined the deposition and depletion in rainbow trout after continuous administration of melamine (MEL) alone or a blend of MEL and cyanuric acid (CYA). The plasma, muscles, kidneys, liver and gills were sampled at 0, 3, 7, 13, 21, 28 and 42d. After the final sampling at 42d, fish from the MEL0.05, MEL20 and MCA groups were fed the control diet (MEL0) for the depletion test. Co-administration with cyanuric acid accelerated the deposition time to the Css for melamine; during the withdrawal phrase, the melamine and CYA concentrations in the tissues decreased exponentially. Compared to the t(½) for single oral administration, the t(½) for melamine and cyanuric acid after 42d continuous feeding was prolonged. The presence of trace CYA in the plasma and kidneys of trout was detected in the MEL20 group, indicating that MEL can convert into CYA in rainbow trout.
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Affiliation(s)
- Haiyan Liu
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China; College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Min Xue
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China; Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Jia Wang
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jing Qiu
- Institute of Quality Standard and Testing Technology for Agro-products, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiufeng Wu
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yinhua Zheng
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junguo Li
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuchang Qin
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China; Institute of Food and Nutrition Development, Ministry of Agriculture, Beijing, China
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An L, Zhang T. Vitamins C and E reverse melamine-induced deficits in spatial cognition and hippocampal synaptic plasticity in rats. Neurotoxicology 2014; 44:132-9. [DOI: 10.1016/j.neuro.2014.06.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/13/2014] [Accepted: 06/13/2014] [Indexed: 02/03/2023]
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9
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Reproductive toxicity in rats with crystal nephropathy following high doses of oral melamine or cyanuric acid. Food Chem Toxicol 2014; 68:142-53. [DOI: 10.1016/j.fct.2014.02.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/20/2014] [Accepted: 02/23/2014] [Indexed: 11/18/2022]
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Wang W, Chen H, Yu B, Mao X, Chen D. Tissue deposition and residue depletion of melamine in fattening pigs following oral administration. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2014; 31:7-14. [DOI: 10.1080/19440049.2013.859399] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Rai N, Banerjee D, Bhattacharyya R. Urinary melamine: proposed parameter of melamine adulteration of food. Nutrition 2013; 30:380-5. [PMID: 24206822 DOI: 10.1016/j.nut.2013.07.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 07/14/2013] [Accepted: 07/15/2013] [Indexed: 12/18/2022]
Abstract
Melamine is widely being reported as a food adulterant. Although its toxicity is currently recognized, melamine adulterations of food items are ongoing for falsely inflating the protein content of the food. Melamine alone or in combination with cyanuric acid or uric acid causes nephrotoxicity, and melamine-induced nephrotoxicity is now a global concern. It has been proven that when consumed, melamine is metabolized at a slower rate and excreted unchanged in urine. There is every possibility that when individuals consume melamine-adulterated food items, the melamine may be excreted unchanged in the urine. Therefore, melamine estimation in urine may be a yardstick to check for melamine adulteration of food items. In the present review, recent literature on this subject is analyzed justifying.
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Affiliation(s)
- Nitish Rai
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Dibyajyoti Banerjee
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
| | - Rajasri Bhattacharyya
- Department of Biotechnology, Maharishi Markandeshwar University, Mullana, Ambala, India
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Dorne JL, Doerge DR, Vandenbroeck M, Fink-Gremmels J, Mennes W, Knutsen HK, Vernazza F, Castle L, Edler L, Benford D. Recent advances in the risk assessment of melamine and cyanuric acid in animal feed. Toxicol Appl Pharmacol 2013; 270:218-29. [DOI: 10.1016/j.taap.2012.01.012] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/22/2011] [Accepted: 01/14/2012] [Indexed: 01/01/2023]
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13
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Zheng X, Zhao A, Xie G, Chi Y, Zhao L, Li H, Wang C, Bao Y, Jia W, Luther M, Su M, Nicholson JK, Jia W. Melamine-induced renal toxicity is mediated by the gut microbiota. Sci Transl Med 2013; 5:172ra22. [PMID: 23408055 DOI: 10.1126/scitranslmed.3005114] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Melamine poisoning has become widely publicized after a recent occurrence of renal injury in infants and children exposed to melamine-tainted milk in China. This renal damage is believed to result from kidney stones formed from melamine and uric acid or from melamine and its cocrystallizing chemical derivative, cyanuric acid. However, the composition of the stones and the mechanism by which the stones are formed in the renal tubules are unknown. We report that cyanuric acid can be produced in the gut by microbial transformation of melamine and serves as an integral component of the kidney stones responsible for melamine-induced renal toxicity in rats. Melamine-induced toxicity in rats was attenuated and melamine excretion increased after antibiotic suppression of gut microbial activity [corrected]. We further demonstrated that melamine is converted to cyanuric acid in vitro by bacteria cultured from normal rat feces; Klebsiella was subsequently identified in fecal samples by 16S ribosomal DNA sequencing. In culture, Klebsiella terrigena was shown to convert melamine to cyanuric acid directly. Rats colonized by K. terrigena showed exacerbated melamine-induced nephrotoxicity. Cyanuric acid was detected in the kidneys of rats administered melamine alone, and the concentration after Klebsiella colonization was increased. These findings suggest that the observed toxicity of melamine may be conditional on the exact composition and metabolic activities of the gut microbiota.
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Affiliation(s)
- Xiaojiao Zheng
- Center for Translational Medicine, and Shanghai Key Laboratory of Diabetes Mellitus, Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
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Landers B, Murarolli R, Gelven R, Brand L, Kobashigaw E, Ledoux D, Bermudez A, Rottinghau G. Individual and Combined Effects of Melamine and Cyanuric Acid in Young Pekin
Ducks. ACTA ACUST UNITED AC 2013. [DOI: 10.3923/ijps.2013.192.201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Pacini N, Prearo M, Abete MC, Brizio P, Dörr AJM, Reimschuessel R, Andersen W, Gasco L, Righetti M, Elia AC. Antioxidant responses and renal crystal formation in rainbow trout treated with melamine administered individually or in combination with cyanuric acid. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2013; 76:491-508. [PMID: 23721584 DOI: 10.1080/15287394.2013.785205] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In 2007 and 2008, renal stone formation and kidney damage in human infants were linked to consumption of melamine (MEL)-contaminated infant formula, as well as renal failure and death in pets due to pet food containing both MEL and cyanuric acid (CYA). The aim of this study was to examine the effects of MEL and CYA administered individually or in combination on concentrations of certain metabolites and enzyme activities that serve as markers for oxidative stress in kidney and liver of rainbow trout. In addition, the levels of muscle MEL and renal crystal formation were determined. Trout were fed MEL and/or CYA for 8 wk at 250, 500, or 1000 mg of each compound/kg in feed. Fish muscle residues of MEL exhibited a dose-response relationship. Coexposure of trout to MEL and CYA at the highest dose led to lower MEL residue concentrations in muscle compared to exposure to MEL alone. Renal MEL-CYA complexes were found in kidneys of fish treated with combined MEL and CYA. A dose response was evident with respect to both (1) number of trout displaying renal crystals and (2) number of crystals per fish. Changes in concentration of antioxidant parameters, such as glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase, were recorded in both tissues of MEL- and CYA-dosed trout. Lipid peroxidation was more pronounced in kidney than liver. Therefore, feed contaminated with both MEL and CYA could be problematic for fish, as MEL administered to trout, individually or in combination with CYA, may facilitate the onset of oxidative damage in trout.
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Affiliation(s)
- Nicole Pacini
- Department of Cellular and Environmental Biology, University of Perugia, Perugia, Italy
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Timing and route of exposure affects crystal formation in melamine and cyanuric exposed male and female rats: Gavage vs. feeding. Food Chem Toxicol 2012; 50:4389-97. [DOI: 10.1016/j.fct.2012.07.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 11/23/2022]
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Landers B, Murarolli R, Gelven R, Brand L, Ledoux D, Bermudez A, Rottinghau G. Effects of Melamine in Young Pekin Ducks. ACTA ACUST UNITED AC 2012. [DOI: 10.3923/ijps.2012.730.738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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Depletion of melamine and cyanuric acid in serum from catfish Ictalurus punctatus and rainbow trout Onchorhynchus mykiss. Food Chem Toxicol 2012; 50:3426-32. [DOI: 10.1016/j.fct.2012.07.055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/26/2012] [Accepted: 07/28/2012] [Indexed: 11/22/2022]
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19
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Repeat oral dose toxicity studies of melamine in rats and monkeys. Arch Toxicol 2012; 87:517-27. [DOI: 10.1007/s00204-012-0939-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 09/06/2012] [Indexed: 10/27/2022]
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20
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Hsieh TJ, Hsieh PC, Tsai YH, Wu CF, Liu CC, Lin MY, Wu MT. Melamine Induces Human Renal Proximal Tubular Cell Injury via Transforming Growth Factor-β and Oxidative Stress. Toxicol Sci 2012; 130:17-32. [DOI: 10.1093/toxsci/kfs231] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Dose-response assessment of nephrotoxicity from a twenty-eight-day combined-exposure to melamine and cyanuric acid in F344 rats. Toxicol Appl Pharmacol 2012; 262:99-106. [PMID: 22579976 DOI: 10.1016/j.taap.2012.04.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/12/2012] [Accepted: 04/24/2012] [Indexed: 11/20/2022]
Abstract
The adulteration of pet food with melamine and derivatives, including cyanuric acid, has been implicated in the kidney failure and death of cats and dogs in the USA and other countries. In a previous 7-day dietary study in F344 rats, we established a no-observed-adverse-effect level (NOAEL) for a co-exposure to melamine and cyanuric acid of 8.6 mg/kg bw/day of each compound, and a benchmark dose lower confidence limit (BMDL) of 8.4-10.9 mg/kg bw/day of each compound. To ascertain the role played by the duration of exposure, we treated F344 rats for 28 days. Groups of male and female rats were fed diet containing 0 (control), 30, 60, 120, 180, 240, or 360 ppm of both melamine and cyanuric acid. The lowest dose that produced histopathological alterations in the kidney was 120 ppm, versus 229 ppm in the 7-day study. Wet-mount analysis of kidney sections demonstrated the formation of melamine cyanurate spherulites in one male and two female rats at the 60 ppm dose and in one female rat at the 30 ppm dose, establishing a NOAEL of 2.1mg/kg bw/day for males and <2.6 mg/kg bw/day for females, and BMDL values as low as 1.6 mg/kg bw/day for both sexes. These data demonstrate that the length of exposure is an important component in the threshold of toxicity from a co-exposure to these compounds and suggest that the current risk assessments based on exposures to melamine alone may not reflect sufficiently the risk of a co-exposure to melamine and cyanuric acid.
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An L, Li Z, Yang Z, Zhang T. Cognitive deficits induced by melamine in rats. Toxicol Lett 2011; 206:276-80. [PMID: 21888959 DOI: 10.1016/j.toxlet.2011.08.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 08/13/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
Abstract
Many studies reported that infants and animals were affected by food containing melamine, and the renal pathology was the main manifestation in intoxicated case. Our previous studies showed that melamine could impair hippocampal function and inhibited differentiated PC12 cell proliferation in vitro. The present study aimed to examine the effect on hippocampus and the possible mechanism induced by melamine in vivo. To address the hypothesis that melamine would impair the hippocampal function in vivo and then induce cognitive deficits, male Wistar rats were used to establish an animal model and melamine administered at a dose of 300 mgkg/day for 4 weeks. Morris water maze (MWM) test was employed to evaluate the learning and memory. The long term potentiation (LTP) from Schaffer collaterals to CA1 region in the hippocampus was recorded. The result of MWM test showed that there were significant deficits of learning and memory induced by melamine. LTP test presented that field excitatory postsynaptic potentials (fEPSPs) slopes were significantly lower in melamine group compared to that in control group. In conclusion, melamine had a toxic influence on hippocampus, which induced the learning and memory deficits. It suggested that the potential mechanism was associated with impairments of synaptic plasticity.
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Affiliation(s)
- Lei An
- College of Life Sciences and Key Lab of Bioactive Materials, Ministry of Education, Tianjin, 300071, PR China
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