Effects of direct electric current on Herpetomonas samuelpessoai: An ultrastructural study

Abstract

The literature shows that the effects of direct electric currents on biological material are numerous, including bactericidal, fungicidal, parasiticidal, and anti-tumoral, among others. Non-pathogenic trypanosomatids, such as Herpetomonas samuelpessoai, have emerged as important models for the study of basic biological processes performed by a eukaryotic cell. The present study reports a dose-dependent anti-protozoan effect of direct electric treatment with both cathodic and anodic current flows on H. samuelpessoai cells. The damaging effects can be attributable to the electrolysis products generated during electric stimulation. The pH of the cell suspension was progressively augmented from 7.4 to 10.5 after the cathodic treatment. In contrast, the anodic treatment caused a pH decrease varying from 7.4 to 6.5. Transmission electron microscopy analyses revealed profound alterations in vital cellular structures (e.g., mitochondrion, kinetoplast, flagellum, flagellar pocket, nucleus, and plasma membrane) after exposure to both cathodic and anodic current flows. Specifically, cathodic current flow treatment induced the appearance of autophagic-like structures on parasite cells, while those submitted to an anodic current flow presented marked disorganization of plasma membrane and necrotic appearance. However, parasites treated in the intermediary chamber (without contact with the electrodes) did not present significant changes in viability or morphology, and no pH variation was detected in this system. The use of H. samuelpessoai as a biological model and the direct electric current experimental approach used in our study provide important information for understanding the mechanisms involved in the cytotoxic effects of this physical agent.

Direct electric current modifies important cellular aspects and ultrastructure features of Candida albicans yeasts: Influence of doses and polarities

“…Previous studies developed with direct electric current indicated the importance of pH variation in tumoral [Veiga et al, ; Cury et al, ; Holandino et al, ] and non‐tumoral damage [Gomes et al, , ]. For that reason, pH variation was registered with the same values of electric charge previously evaluated in cell viability experiments.…”

“…In the present work, DC effects on C. albicans were evaluated using platinum electrodes since it is an inert material and consequently does not induce ion release in the electrolytic medium, facilitating DC mechanism comprehension, as previously registered in bacteria [Holandino et al, ; Gomes et al, ] and protozoa [Gomes et al, ] samples. The viability assays were performed by two methods: plating to quantify CFUs and propidium iodide (PI) incorporation.…”

“…DC microbicide effect has been evaluated in different bacteria species [Bolton et al, 1980;Chu et al, 1988;Liu et al, 1993;Holandino et al, 1998] and protozoa [Hejazi et al, 2004;Gomes et al, 2012]. Additionally, previous published works showed C. albicans'damage, including inactivation of important enzymes due to electrolytic silver ions generated by anodic flow [Berger et al, 1976;Aydin et al, 1997;Devrim SeS cinti et al, 2009].…”

“…When it comes to fungus, previous papers showed DC susceptibility of C. albicans , especially when treated with silver electrodes [Berger et al, ; Aydin et al, ; Devrim Seçinti et al, ]. DC effects are also related to polarity and intensity in different cellular models, including tumoral cells, protozoa, and bacteria [Veiga et al, ; Gomes et al, ; Ciria et al, ; Cury et al, ; Holandino et al, ].…”

“…Other DC effects demonstrated growth inhibition of different protozoa and bacteria species, both in animal and in vitro models [Bolton et al, 1980;Chu et al, 1988;Liu et al, 1993;Holandino et al, 1998;Hejazi et al, 2004;Gomes et al, 2012]. On the other hand, DC can also display a regenerative action, with interesting clinical results in ulcer healing [Gault and Gatens, 1976;Lee et al, 1993;Fraccalvieri et al, 2015].…”