Resistance towards calcium induced bilirubin dependent hemolysis in porcine erythrocytes

Hemolysis of erythrocytes from human and porcine blood was studied at different calcium chloride (CaCl(2)) concentrations (0.04-1.83 mM) and at a constant bilirubin concentration (72 mM). Although, human erythrocytes showed significant hemolysis (64%) at the highest CaCl(2) concentration (1.83 mM) used in this study, remarkable resistance to this phenomenon was observed with porcine erythrocytes as only 11% hemolysis was observed. A similar pattern in the behavior of both human and porcine erythrocytes was observed when parameter such as bilirubin concentration or time of incubation with bilirubin was varied. Other divalent cations such as Mn(2+), Ba(2+) and Mg(2+) were either least effective or ineffective in inducing hemolysis in presence of bilirubin. Serum albumin played a protective role in this phenomenon in a concentration dependent manner, as no hemolysis was observed at a bilirubin/albumin molar ratio of 1:1 or less. Differences in the structural make-up of proteins and lipids in the erythrocyte membranes of the two species may account for their different behavior.