[The changes in erythrocyte calcium is one of the mechanisms of anemia formation in rabbit endotoxin-induced DIC].
The effects of E. coli endotoxin (ET) on human erythrocyte cytosolic free calcium concentration ([Ca2+]i) and membrane calcium pump (Ca(2+)-Mg(2+)-ATPase) activity were observed in vitro. The changes of erythrocyte [Ca2+]i, Ca(2+)-Mg(2+)-ATPase activity, calmodulin activity, the deformability of erythrocytes, membrane protein electrophoresis, and the fluidities of membrane lipids were investigated in the ET-induced disseminated intravascular coagulation (DIC) model to study the significance of erythrocyte factors in the occurrence of microangiopathic hemolytic anemia. The [Ca2+]i of human erythrocytes was 86 +/- 9.2 nmol/L in normal cells, and it was increased to 124 +/- 22 nmol/L, 174 +/- 41 nmol/L and 220 +/- 92.1 nmol/L, respectively, when the erythrocytes were incubated with 0.5 mg/ml, 1 mg/ml and 2 mg/ml ET, respectively. At the same time, the Ca(2+)-Mg(2+)-ATPase activities decreased from 1031 +/- 131 nmol/mg.h in normal to 870 +/- 182 nmol/mg.h, 684 +/- 124 nmol/mg.h and 718 +/- 144.4 nmol/mg.h in groups receiving 0.5 mg/ml, 1 mg/ml and 2 mg/ml ET, respectively (P < 0.01). The [Ca2+]i of rabbit erythrocytes was elevated from 76.6 +/- 14.9 nmol/L in normal to 224 +/- 74 nmol/L (P < 0.01), and the Ca(2+)-Mg(2+)-ATPase activity was inhibited from 220 +/- 26.8 nmol/mg.h in normal to 146.1 +/- 30.6 nmol/mg.h during ET-induced DIC in vivo. In addition, erythrocyte deformability decreased and the membrane protein electrophoresis showed changes in the 4.5 KD band area. However, there was no significant difference in the calmodulin activity and fluidities of membrane lipids of erythrocytes in DIC rabbits. These results suggest a possible alternative mechanism for the formation of microangiopathic hemolytic anemia in ET-induced DIC rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)
Wang
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Y
Faculty of Basic Medicine, PUMC, Beijing.
D000328:Adult; D000743:Anemia, Hemolytic / Q000209:etiology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000097:blood; D002118:Calcium / Q000097:blood*; D002147:Calmodulin / Q000097:blood; D004211:Disseminated Intravascular Coagulation / Q000097:blood* / Q000139:chemically induced / Q000150:complications; D004731:Endotoxins; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000378:metabolism*; D004926:Escherichia coli; D005260:Female; D006801:Humans; D008297:Male; D011817:Rabbits
D002147:Calmodulin; D004731:Endotoxins; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium