ABSTRACT
Polyvinylpyridine-N-oxide (PVPNO) and carboxymethyl cellulose (CMC) are known to inhibit the cytotoxic effects of quartz particles and chrysotile asbestos fibers, respectively. The effect of PVPNO and CMC on mineral dust-induced production of reactive oxygen species (ROS) by human monocyte-derived macrophages was studied using lucigenin-dependent chemiluminescence. Ten micrograms of PVPNO inhibited the ROS production induced by 100 micrograms of quartz completely, but caused only 25% inhibition of the response to 100 micrograms of chrysotile. Ten micrograms of CMC inhibited the chrysotile-induced ROS production to 70%, but had a weak effect on the responses to quartz. Neither PVPNO nor CMC caused any inhibition of the ROS responses to serum-opsonized zymosan. PVPNO was bound to both quartz and chrysotile, but no binding of CMC to either dust could be detected. Neither PVPNO nor CMC had any superoxide scavenging effect. In conclusion, PVPNO and CMC seem to selectively modify mineral dust surface properties, which are of importance in the induction of ROS production by phagocytes. These observations may be useful in describing the pathogenesis of mineral dust-induced diseases, and may also have therapeutic implications.
Subject(s)
Carboxymethylcellulose Sodium/pharmacology , Dust , Macrophages/metabolism , Minerals/pharmacology , Oxygen/metabolism , Polyvinylpyridine N-Oxide/pharmacology , Asbestos/metabolism , Asbestos, Serpentine , Cells, Cultured , Humans , Luminescent Measurements , Macrophages/drug effects , Polyvinylpyridine N-Oxide/metabolism , Quartz/metabolism , Zymosan/pharmacologyABSTRACT
The biological activity of montmorillonite, palygorskite, kaolinite, chrysotile, and silica was examined using in vitro hemolysis of erythrocytes. The hemolytic potency was in the order montmorillonite greater than silica greater than palygorskite greater than chrysotile greater than kaolinite. The polymer poly-2-vinylpyridine-N-oxide inhibited hemolysis caused by montmorillonite, palygorskite, kaolinite, and silica, but it was less effective with chrysotile. The extent of polymer binding to the silicates and red blood cells was measured by UV spectroscopy. When sucrose was substituted for the saline solution as the incubating medium, hemolysis was eliminated in all systems except chrysotile-erythrocyte, where it was enhanced. The results indicate that both hydrogen bonding and ionic interactions between silicate surfaces and the erythrocyte membrane are important in the hemolytic process.
