| Intracellular influx of calcium induced by quartz particles in alveolar macrophages. | |
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MedLine Citation:
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PMID: 19835900 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Historical studies report that cellular injury and silicosis are related to cytosolic free calcium (Ca2+). Moreover, reactive oxygen species (ROS) have been linked to cellular injury. However, the detail mechanism of the increase in [Ca2+]i and the relationship between [Ca2+]i and ROS production remains unknown. Quartz particle has been found to increase [Ca2+]i and activate the generation of ROS. Our hypothesis is that [Ca2+]i increase induced by quartz particle is from extracellular Ca2+ through the Ca2+ channel, and [Ca2+]i increase is believed to activate ROS production. In order to examine this hypothesis, we treated rat alveolar macrophages with quartz (SiO2) particles and used laser scanning confocal microscopy to measure [Ca2+]i and the fluorescence intensity of ROS. Time- and dose-dependent increases in [Ca2+]I and ROS in macrophages as well as cell viability were observed. Through chelating extracellular Ca2+ with ethylene glycol tetraacetic acid and releasing intracellular Ca2+ with thapsigargin, we found that 72.7% of the [Ca2+]i increase was due to the influx of Ca2+ from the extracellular environment, via Ca2+ channels in the plasma membrane. By adding mannitol to scavenge hydroxyl radicals (OH(.)), and removing surface iron from the quartz particles to reduce OH(.) generation, we observed a reduced level of ROS generation, whereas the increase in [Ca2+]i was unaffected. When using EGTA to reduce [Ca2+]i, we observed a decrease in ROS production. This study suggests that the [Ca2+]i influx was independent of OH(.) production, and the [Ca2+]i increase resulted in ROS production. These results further indicate that there is a strong relationship between cytosolic free Ca2+ content and cellular injury as well as silica exposure. |
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Authors:
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Feng Tian; Tong Zhu; Yu Shang |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-10-14 |
Journal Detail:
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Title: Toxicology and applied pharmacology Volume: 242 ISSN: 1096-0333 ISO Abbreviation: Toxicol. Appl. Pharmacol. Publication Date: 2010 Jan |
Date Detail:
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Created Date: 2009-12-07 Completed Date: 2009-12-15 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0416575 Medline TA: Toxicol Appl Pharmacol Country: United States |
Other Details:
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Languages: eng Pagination: 173-81 Citation Subset: IM |
Affiliation:
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State Key Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Bronchoalveolar Lavage Fluid Calcium / metabolism* Ion Transport Macrophages, Alveolar / metabolism* Male Quartz* Rats Rats, Sprague-Dawley Reactive Oxygen Species / metabolism |
| Chemical | |
Reg. No./Substance:
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0/Reactive Oxygen Species; 14808-60-7/Quartz; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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