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Manganese-induced Oxidative Stress in the Corpus Striatum of the Rat Brain
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Soo Jin Lee, Soon Oh Hong, Hyun Chul Koh
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Korean Journal of Occupational and Environmental Medicine 2002;14(1):23-33. Published online March 31, 2002
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DOI: https://doi.org/10.35371/kjoem.2002.14.1.23
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 Abstract
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- OBJECTIVES
This study was undertaken to identify the effect of oxidative stress on the pathology of manganese intoxication through an analysis of manganese concentrations, superoxide dismutase (SOD) activities, malondialdehyde (MDA) concentrations, and the compositional changes of fatty acids from the corpus striatum of the rat brain.
METHODS
Ten Sprague-Dawley rats were equally divided into two groups. Five rats in the experimental group were administered MnCl2 intraperitoneally for 4 weeks (4 mg/kg once daily, 5 days per week) and another five rats from the control group were given normal saline. Twenty-four hours after the last injection, the rats were decapitated and, the corpus striatum was isolated from the brain.
RESULTS
In the corpus striatums of the experimental group, manganese concentrations increased significantly by 139 % (p<0.01). The SOD activities decreased significantly by 81 % (p<0.01) and the MDA concentrations increased significantly by 138 % (p<0.01) as compared to the control group. Among fatty acids, total n-6 polyunsaturated fatty acids (PUFAs) increased significantly by 325 % (p<0.01) as compared with the control group. Arachidonic acids (AA) increased by 341 % (p<0.01), and these increases were composed mostly of n-6 polyunsaturated fatty acids (PUFA). Among n-3 PUFAs, with the exception of linolenic acids, eicosapentanoic acid (EPA) decreased significantly by 72 % (p<0.05) and docosahexanoic acids (DHA) decreased by 67 % (p<0.05) as compared with the control group.
CONCLUSIONS
Our results suggest that the oxygen free radicals produced by manganese may cause compositional changes of fatty acids in the corpus striatum of the rat brain. The characteristics of the fatty acids'compositional changes by manganese were a decrease of EPAs and DHAs (n-3 PUFAs), and an increase of AAs (n-6 PUFAs). These changes coupled with the decrease of SOD activity and the increase of MDA, suggest that manganese neurotoxicity is caused by lipid peroxidation mediated with oxygen free radicals, particularly superoxide radicals.
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Changes of Superoxide Dismutase Activity in Cadmium-induced Acute Nephrotoxicity of Rats
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Soo Jin Lee, Hyun Chul Koh, Chung Yill Park
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Korean Journal of Occupational and Environmental Medicine 2001;13(4):393-400. Published online December 31, 2001
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DOI: https://doi.org/10.35371/kjoem.2001.13.4.393
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Abstract
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- OBJECTIVES
To investigate the role of superoxide dismutase(SOD) in the pathogenesis of cadmium-induced acute nephrotoxicity.
METHODS
Rats treated with a single intraperitoneal injection of cadmium(as CdCl2, 1 mg/kg) were included in the cadmium-treated group; the control group comprised untreated rats. 24-hour urine samples were obtained prior to sacrifice on days 1, 2, 4, 8 and 16(N = 10 per group), respectively. The activity of SOD and concentration of cadmium were measured in the homogenates of the renal cortex. Nephrotoxicity indices such as N-acetyl-beta-D-glucosaminidase(NAG) activity, total protein, and 24-hour urine volume, and the cadmium concentrations in the urine were measured.
RESULTS
The cadmium injection caused a significant increase of cadmium concentration in the renal cortex on days 1 and 2, and in the urine on days 1, 2 and 4. The NAG activities and total protein concentrations in urine were significantly increased on days 1, 2 and 4, and on days 1, 4 and 8, respectively. The peak values of NAG activity and total protein in urine were observed on days 1 and 4, respectively. A significant decrease of 24- hour urinary volume was induced on day 1. Renal SOD activity was significantly inhibited on day 1. Finally, on day 8, SOD activity was significantly increased and all nephrotoxicity indices except urinary total protein returned to the control level.
CONCLUSIONS
These results suggest that cadmium induces initial depression of SOD enzyme activities in the renal cortex followed by a later activation, and that the initial depression of this enzyme plays an important role in mediating the proteinuric injury of cadmium-induced acute nephrotoxicity.
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