US EPA

3100599 

Journal Article 

Interactions of chrysotile and crocidolite asbestos with red blood cell membranes: Chrysotile binds to sialic acid 

Brody, AR; George, G; Hill, LH 

1983 

1 

Laboratory Investigation
ISSN: 0023-6837
EISSN: 1530-0307 

WILLIAMS & WILKINS 

BALTIMORE 

HEEP/84/05211 

49 

4 

468-475 

English 

6312192 

WOS:A1983RM13000012 

HEEP COPYRIGHT: BIOL ABS. Chrysotile and crocidolite are commonly used forms of asbestos. Hemolysis has been widely used as a test of membrane injury, and it has been shown that chrysotile causes rapid breakdown of red blood cells (RBC); crocidolite is only weakly hemolytic. A reasonable hypothesis set forth to explain the cytotoxic effects of chrysotile maintains that positively charged chrysotile fibers bind to negatively charged sialic acid residues on RBC membranes causing clustering of membrane proteins and increased cell permeability to Na and K ions. Morphologic ultrastructural techniques showed that chrysotile and crociodolite asbestos bound to and distorted and gt; 85% of rat RBC treated for 15 min. The distorting effects of chrysotile, but not crocidolite, were almost totally ablated by pretreating the cells with neuraminidase. Au-conjugated wheat germ agglutinin was used to label the distribution of sialic acid groups on RBC membranes. Pretreatment of RBC with chrysotile, but not crociodolite, reduced the number of Au-conjugated wheat germ agglutinin-labeled sites to and lt; 30% of the control level. The thiobarbituric acid assay was used to determine the percentage of sialic acid that remained with the cell pellet after neuraminidase and/or asbestos treatment. Asbestos treatment alone caused no release of sialic acid from the cells. Neuraminidase treatment for 3.5 h removed and gt; 80% of the sialic acid from cell surfaces. Chrysotile, but not crocidolite, asbestos prevented neuraminidase-mediated removal of sialic acid from RBC. X-ray energy spectrometry of freeze-dried cells showed that RBC distorted by chrysotile, but not by crocidolite, exhibited significant alterations in intracellular Na:K ratios. The morphologic and biochemical data strongly supported the hypothesis that chrysotile asbestos bound to sialic acid groups on RBC membranes. The sialic acid residues were redistributed on the surfaces of distorted cells which were unable to maintain a normal Na:K balance with the surrounding medium. 

Asbestos, Serpentine; Membrane Proteins; Sialic Acids; Asbestos, Crocidolite; 12001-28-4; Asbestos; 1332-21-4; Silicon Dioxide; 7631-86-9; 9NEZ333N27; Neuraminidase; EC 3.2.1.18; Potassium; RWP5GA015D; Index Medicus; Membrane Proteins -- blood; Animals; Sodium -- blood; Silicon Dioxide -- toxicity; Erythrocytes, Abnormal -- ultrastructure; Potassium -- blood; Neuraminidase -- pharmacology; Sialic Acids -- blood; Asbestos -- blood; Erythrocyte Membrane -- drug effects; Erythrocyte Membrane -- ultrastructure; Erythrocyte Membrane -- metabolism; Asbestos -- toxicity