Aim: 

Fish erythrocytes are cells easily exposed to oxidative agents. Such stress involves cell shrinkage by activation of K-Cl cotransport, micronuclei formation, changes on band 3-mediated anion transport. The aim of our study was to obtain evidence of this oxidative stress influence on fish erythrocytes treated with different agents as CdCl, MgCl₂, selenium and crude venom extracted from isolated nematocysts of the Scyphozoan Pelagianoctiluca whose biological activity has been already demonstrated.

Methods: 

Erythrocytes of goldfish Carassius auratus (Cyprinidae) were alternatively treated with either CdCl or selenium or MgCl₂ or crude venom from Pelagia noctiluca nematocysts and then tested for sulphate uptake, K⁺ efflux and micronuclei development. SO₄ = was measured by atomic absorption at 425 nm wavelength. K⁺ efflux was measured by flame photometer. Micronuclei formation was detected by light microscope observations.

Results: 

In fish erythrocytes the "rate constant" of SO₄ = uptake (0.027 min^-1) was decreased by 31% when cells were incubated with either Cd⁺ (0.016 min^-1) or selenium or 0.5 ml of Pelagia noctiluca venom. Whereas the "rate constant" was increased by 15% when cells were treated with exogenous Mg²⁺. The oxidative agents Cd⁺ and selenium increased K⁺ efflux whereas Mg²⁺ did not as well as Pelagia noctiluca crude venom. Finally the oxidative agents and venom drastically induced micronuclei formation whereas Mg²⁺ did not.

Conclusions: 

The decreased SO₄ = uptake observed in treated cells could be a consequence of either band 3 protein oxidation or oxidative stress induced by KCl symport–mediated cell shrinkage or concomitant formation of intracellular micronuclei and cell membrane alterations.