Mercury chloride effects on the function and cellular integrity of sea bass (Dicentrarchus labrax) head kidney macrophages

The objective of this work was to study mercury chloride effects on the function and integrity of sea bass (Dicentrarchus labrax) head kidney macrophages (S-HKM), and to evaluate the response of HgCl2-exposed cells to macrophage activating factor(s) (MAF) produced by sea bass head kidney leukocytes. There was considerable variability in the effects of HgCl2 on the production of reactive oxygen species (ROS) by S-HKM. When incubated with HgCl2, cells from five out of nine fish tested showed a decrease in ROS production as compared to cells incubated with medium alone. In those cultures, MAF addition prevented the mercury chloride-induced decrease in ROS production. In other S-HKM cultures isolated from different fish, mercury chloride abrogated the up-regulating effect of MAF on the respiratory burst. MAF activation of the phagocytic activity of S-HKM was also impaired by HgCl2 addition. Mercury chloride induced apoptosis in S-HKM cultures and MAF addition prevented this effect.