In vitro and in vivo haemolytic studies of tentacle-only extract from jellyfish Cyanea capillata

To approach the real haemolytic process of jellyfish toxins, both in vitro and in vivo haemolysis of tentacle-only extract (TOE) from jellyfish Cyanea capillata has been studied. Dose-response curves of the haemolytic activity of TOE in vitro were sigmoid shaped in both erythrocyte suspension and diluted whole blood, with the former more sensitive to TOE. The in vivo haemolysis increased sharply in the first 10 min and was followed by a gradual increase in the following 3 h, with increasing blood potassium and lactic acid accordingly. SC5b-9 complexes were significantly up-regulated in vitro, but not in vivo. These results showed that the haemolysis of TOE in diluted whole blood and in vivo is not totally consistent with that in the erythrocyte suspension, and blood plasma might play a protective role against haemolysis. Thus we suggested that erythrocyte suspension can be used to test the damage of toxin on erythrocyte membrane, while the diluted whole blood may be more suitable to test the haemolysis of toxins.