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Kim WI, Pak SW, Lee SJ, Moon C, Shin IS, Lee IC, Kim JC. Effects of melamine and cyanuric acid on placental and fetal development in rats. Food Chem Toxicol 2023:113862. [PMID: 37247804 DOI: 10.1016/j.fct.2023.113862] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/10/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
Melamine or cyanuric acid alone has low toxicity, but combined exposure to melamine and cyanuric acid was reported to cause unexpected toxicological effects. This study investigated the potential effects and toxic mechanism of combined exposure to melamine and cyanuric acid on placental and fetal development in rats. Exposure to melamine and cyanuric acid caused maternal toxicity manifested by increased abnormal symptoms and decreased body weight gain. Developmental toxic effects included a decrease in placental and fetal weights with increased fetal deaths and post-implantation loss. Melamine and cyanuric acid induced oxidative stress in the developing placenta and fetus. The placentas from rats treated with melamine and cyanuric acid showed shortening of the placental layers with histological changes, decreased cell proliferation, increased apoptotic changes, and decreased insulin-like growth factor (IGF)/IGF-binding proteins (IGFBPs) and placental lactogen (PL) expression levels. Fetuses from melamine- and cyanuric acid-treated dams showed increased apoptotic changes and suppressed cellular proliferation in their livers and vertebrae. Consequently, combined exposure to melamine and cyanuric acid resulted in high levels of oxidative stress and impaired placental development associated with impairment of the IGF/IGFBP and PL systems, resulting in increased apoptotic changes and reduced fetal cell proliferation.
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Affiliation(s)
- Woong-Il Kim
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - So-Won Pak
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Se-Jin Lee
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Changjong Moon
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - In-Sik Shin
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - In-Chul Lee
- Functional Biomaterial Research Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea.
| | - Jong-Choon Kim
- College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju, 61186, Republic of Korea.
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Prenatal cyanuric acid exposure disrupts cognitive flexibility and mGluR1-mediated hippocampal long-term depression in male rats. Toxicol Lett 2022; 370:74-84. [PMID: 36152796 DOI: 10.1016/j.toxlet.2022.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 08/24/2022] [Accepted: 09/20/2022] [Indexed: 11/20/2022]
Abstract
Cyanuric acid is one of the most widely used classes of industrial chemicals and is now well known as food adulterant and contaminant in pet food and infant formula. Previously, it was reported that animals prenatally exposed to cyanuric acid showed neurotoxic effects that impaired memory consolidating and suppressed long-term potentiation (LTP) in the hippocampus. However, it is not clear if prenatal exposure to cyanuric acid induces deficits in reversal learning and long-term depression (LTD), which is required for the developmental reorganization of synaptic circuits and updating learned behaviors. Here, pregnant rats were i.p. injected with cyanuric acid (20 mg/kg) during the whole of gestation, and male offspring were selected to examine the levels of hippocampal mGluR1 and mGluR2/3 in young adulthood. The LTD at the Schaffer collateral-CA1 pathway was induced by low-frequency stimulation (LFS) and recorded. Reversal learning and hippocampus-dependent learning strategy were tested in Morris-water maze (MWM) and T-maze tasks, respectively. To further confirm the potential mechanism, selective agonists of mGluR1 and mGluR2/3 and antagonists of mGluR were intra-hippocampal infused before behavioral and neuronal recording. We found the levels of alkaline phosphatase were markedly increased in the maternal placenta and fetal brain following prenatal exposure. The expression of mGluR1 but not mGluR2/3 was significantly decreased and mGluR1-mediated LTD was selectively weakened. Prenatal cyanuric acid impaired reversal learning ability, without changing place learning strategy. The mGluR1 agonist could effectively enhance LFS-induced LTD and mitigate reversal learning deficits. Meanwhile, the reductions in the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPAR)-mediated spontaneous excitatory postsynaptic currents (sEPSCs) amplitude and frequency of cyanuric acid offspring were simultaneously alleviated by mGluR1 agonist infusions. Therefore, the results indicate the cognitive and synaptic impairments induced by prenatal cyanuric acid exposure are attributed to the disruption of the hippocampal mGluR1 signaling. Our findings provided the first evidence for the deteriorated effects of cyanuric acid on synaptic depression and advanced cognitive performance.
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Wu CF, Cheng CM, Hsu YM, Li SS, Huang CY, Chen YH, Kuo FC, Wu MT. Development of analytical method of melamine in placenta from pregnant women by isotope-dilution liquid chromatography/tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34 Suppl 1:e8599. [PMID: 31677293 DOI: 10.1002/rcm.8599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/08/2019] [Accepted: 09/12/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Melamine is ubiquitously present in our daily life. It has a known effect on the kidneys, but it may also adversely affect the reproduction system. We have developed an analytical method for measuring melamine levels in maternal placenta and correlated these levels with melamine concentrations in urine, a necessary step in finding out if melamine might cross the placenta and enter the circulation of the fetus. METHODS We used liquid-liquid extraction, clean up by solid-phase extraction (SPE), and isotope-dilution liquid chromatography/tandem mass spectrometry (LC/MS/MS) to measure melamine in placenta specimens. The results of this method were assessed for linearity, limits of quantitation (LOQs), and intra- and inter-assay precision as well as accuracy, matrix effect, and recovery rate. RESULTS Calibration curves indicated good linearity (r >0.995) over concentrations ranging from 5 to 500 ng/mL in placenta specimens, intra- and inter-assay precision from 0.89% to 27.07%, and accuracy from 92.4% to123.5%. Recovery ranged from 63.9 to 83.9%, and the LOQ was 5 ng/mL in placenta (0.2 g). Placental melamine levels ranged from 7.87 to19.64 ng/mL, all detectable (n = 8). Pregnant women with higher levels of urinary melamine had higher placenta melamine levels than those with non-detectable urinary melamine, though the results were not significantly different (p = 0.149, n = 4 in each group). CONCLUSIONS The results of this study suggest that pregnant women were exposed to low doses of melamine in their daily lives as measured in urine samples and placenta specimens. It is unclear whether placenta melamine concentrations can better represent long-term exposure than urine or whether melamine in the uterus can enter the fetus via this route.
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Affiliation(s)
- Chia-Fang Wu
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ching-Mei Cheng
- Department of Laboratory Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan
| | - Yu-Ming Hsu
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Sih-Shyan Li
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chung-Yi Huang
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yung-Hung Chen
- Department of Gynecology and Obstetrics, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan
| | - Fu-Chen Kuo
- Department of Gynecology and Obstetrics,, E-Da Hospital,, Kaohsiung, Taiwan
- School of Medicine,, College of Medicine, I-Shou University,, Kaohsiung, Taiwan
| | - Ming-Tsang Wu
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Community Medicine,, Kaohsiung Medical University Hospital, Kaohsiung Medical University,, Kaohsiung, Taiwan
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Chu CY, Fung KP, Wang CC. Effects of low-dose melamine exposure during pregnancy on maternal and fetal kidneys in rats. ENVIRONMENTAL TOXICOLOGY 2018; 33:370-380. [PMID: 29265596 DOI: 10.1002/tox.22525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 11/29/2017] [Accepted: 12/02/2017] [Indexed: 06/07/2023]
Abstract
Despite the previous reports on melamine contamination in high concentrations some years ago, there were not many studies on low-level exposure in daily life, particularly in pregnancy. We investigated the effect of low-dose melamine on the kidneys of the pregnant rats and their developing embryos/fetuses during various gestational stages namely implantation, gastrulation, organogenesis, maturation and whole pregnancy. Our results showed that the repeated low level of melamine (12.5, 25, and 50 mg/kg bw/d) during pregnancy did not cause obstruction of renal tubules although more precipitating crystals were found in the early gestational periods. Simple hyperplasia in the maternal tubules and pelvic epithelium were more prominent after exposed to melamine during the whole gestational period. Neonatal kidneys significantly suffered more from congestion in glomeruli and interstitium, dilated tubules and interstitial edema after melamine administration to the mother in the late and the whole gestational periods. A trend of advance of glomerular development in fetuses was also observed. We conclude that in utero exposure of low-level melamine could post a risk on the kidneys of the pregnant mother as well as the developing fetuses, which may further increase the possibility of other health problems later in life.
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Affiliation(s)
- Ching Yan Chu
- Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Hong Kong
| | - Kwok Pui Fung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Hong Kong
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong
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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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Tian XY, Wong WT, Lau CW, Wang YX, Cheang WS, Liu J, Lu Y, Huang H, Xia Y, Chen ZY, Mok CS, Lau CM, Huang Y. Melamine Impairs Renal and Vascular Function in Rats. Sci Rep 2016; 6:28041. [PMID: 27324576 PMCID: PMC4914856 DOI: 10.1038/srep28041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 05/26/2016] [Indexed: 12/11/2022] Open
Abstract
Melamine incident, linked to nephrotoxicity and kidney stone in infants previously exposed to melamine-contaminated milk products, was unprecedentedly grave in China in 2008 as little was known about the mechanistic process leading to renal dysfunction in affected children. This study investigates whether neonatal ingestion of melamine leads to renal and vascular dysfunction in adulthood; and whether ingestion of melamine in pregnant rats leads to renal dysfunction in their offspring. A combination of approaches employed includes functional studies in rat renal arteries, renal blood flow measurement by functional magnetic resonance imaging, assay for pro-inflammatory and fibrotic biomarkers, immunohistochemistry, and detection of plasma and renal melamine. We provide mechanistic evidence showing for the first time that melamine reduces renal blood flow and impairs renal and vascular function associated with overexpression of inflammatory markers, transforming growth factor-β1, bone morphogenic protein 4 and cyclooxygenase-2 in kidney and renal vasculature. Melamine also induces renal inflammation and fibrosis. More importantly, melamine causes nephropathies in offsprings from pregnant rat exposed to melamine during pregnancy, as well as in neonatal rat exposed to melamine afterbirth, thus supporting the clinical observations of kidney stone and acute renal failure in infants consuming melamine-contaminated milk products.
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Affiliation(s)
- Xiao Yu Tian
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Wing Tak Wong
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Chi Wai Lau
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Yi-Xiang Wang
- Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Hong Kong
| | - Wai San Cheang
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Jian Liu
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Ye Lu
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Huihui Huang
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Yin Xia
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
| | - Zhen Yu Chen
- School of Life Sciences, Chinese University of Hong Kong, Hong Kong
| | | | | | - Yu Huang
- School of Biomedical Sciences, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong
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