Haemocyte apoptosis as a general cellular immune response of the snail, Lymnaea stagnalis, to a toxicant.
The effects of a xenobiotic on the circulating haemocytes of Lymnaea stagnalis were investigated after short-term (24 h, 96 h) and long-term (504 h) exposure of snails to environmental concentrations. Fomesafen, a pro-oxidant generator led to the activation of the haemocyte apoptotic program by promoting reactive oxygen species (ROS). Cells entering apoptosis underwent a series of events, both on the plasma membrane and in the mitochondria; these events were quantified by flow cytofluorometry. The data showed a loss of mitochondrial transmembrane potential (Deltapsim), which was dose-dependent and time-dependent and related to an increased release of superoxide anions. The phosphatidylserine that was exposed at the outer plasma membrane was not related to the disruption of either ROS or Deltapsim but was strongly correlated with the haemocyte concentration (total haemocyte count). This cascade of apoptotic processes occurred in a dose-independent manner and was not strengthened over time. The increase of circulating haemocytes depended upon the life span of the cells and might have reflected either facilitated cell turn-over or the accompanying presence of haemocytes phagocytosing apoptotic cells.
Russo
Jacqueline
J
UMR 6553 Ecobio, Equipe Evolution des Histoires de Vie, CNRS Université de Rennes1, Campus de Beaulieu, Avenue du Général Leclerc, Rennes, France. jacqueline.russo@univ-rennes1.fr
Madec
Luc
L
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides / Q000633:toxicity*; D001772:Blood Cell Count; D005434:Flow Cytometry; D006434:Hemocytes / Q000166:cytology*; D007109:Immunity / Q000187:drug effects*; D008195:Lymnaea / Q000187:drug effects* / Q000276:immunology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism
D017304:Annexin A5; D001549:Benzamides; D017382:Reactive Oxygen Species; C088563:fomesafen