Comparison of hemocyte parameters in the pericardial cavity and the adductor muscle sinus in the Pacific oyster, Crassostrea gigas using two types of flow cytometers

¹ Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés, UMR 6217, avenue Michel Crépeau, 17042 La Rochelle, France
² IFREMER La Tremblade, Laboratoire de Génétique et Pathologie, 17390 La Tremblade, France
³ Laboratoire des Sciences de l'Environnement Marin, UMR CNRS 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, place Nicolas Copernic, 29280 Plouzané, France
⁴ Institut Armand-Frappier, Institut National de la Recherche Scientifique, Campus de Pointe-Claire, 245 Hymus, Pointe-Claire, H9R 1G6, Québec, Canada

Corresponding author: trenault@ifremer.fr

Received: 4 October 2007
Accepted: 4 December 2007

Abstract

Parameters of hemocyte populations have been considered as relevant indicators of bivalve health and are currently used in immunotoxicological studies. Hemocytes in hemolymph can be collected by puncturing either the pericardial cavity or the adductor muscle sinus with a syringe. Flow cytometry is a methodological approach that is increasingly being used in laboratories for the study of hemocyte parameters in aquatic invertebrates. However, various protocols for hemocyte processing in laboratories equipped with different types of cytometers have been published. In this context, two flow cytometers (EPICS XL4®, Beckman Coulter and FacsCalibur®, Becton Dickinson) and two sites of hemocyte collection (pericardial cavity and adductor muscle sinus) were compared for the analysis of hemocyte parameters in the Pacific oyster, Crassostrea gigas. Hemolymph cells were analyzed in terms of their number and organelle contents. Cell mortality, phagocytosis, non specific esterase, extension of the lysosomal compartment and production of reactive oxygen species were quantified. The results showed that the phagocytic index was higher for hemocytes obtained in the muscle sinus hemolymph. The results are discussed with respect to the potential use of flow cytometry as a tool for hemocyte studies in bivalves.