title: Assessment of oxidant susceptibility of red blood cells in various species based on cell deformability.
abstract: The present study was designed to investigate the oxidant susceptibility of red blood cells (RBC) from four species (echidna, human, koala, Tasmanian devil) based on changes in cellular deformability. These species were specifically chosen based on differences in lifestyle and/or biology associated with varied levels of oxidative stress. The major focus was the influence of superoxide radicals generated within the cell (phenazine methosulfate, PMS, 50 μM) or in the extracellular medium (xanthine oxidase-hypoxanthine, XO-HX, 0.1 U/ml XO) on RBC deformability at various shear stresses (SS). RBC deformability was assessed by laser-diffraction analysis using a "slit-flow ektacytometer". Both superoxide-generating treatments resulted in significant increases of methemoglobin for all species (p < 0.01), with Tasmanian devil RBC demonstrating the most sensitivity to either treatment. PMS caused impaired RBC deformability for all species, but vast interspecies variations were observed: human and koala cells exhibited a similar sigmoid-like response to SS, short-beaked echidna values were markedly lower and only increased slightly with SS, while Tasmanian devil RBC were extremely rigid. The effect of XO-HX on RBC deformability was less when compared with PMS (i.e., smaller increase in rigidity) with the exception of Tasmanian devil RBC which exhibited essentially no deformation even at the highest SS; Tasmanian devil RBC response to XO-HX was thus comparable to that observed with PMS. Our findings indicate that ektacytometry can be used to determine the oxidant susceptibility of RBC from different species which varies significantly among mammals representing diverse lifestyles and evolutionary histories. These differences in susceptibility are consistent with species-specific discrepancies between observed and allometrically-predicted life spans and are compatible with the oxidant theory of aging.
authors.affiliation: Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Simmonds
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
authors.forename: Sonya M
authors.initials: SM
authors.lastname: Marshall-Gradisnik
authors.forename: Michael
authors.initials: M
authors.lastname: Pyne
authors.forename: Michael
authors.initials: M
authors.lastname: Kakanis
authors.forename: James
authors.initials: J
authors.lastname: Keane
authors.forename: Ekua
authors.initials: E
authors.lastname: Brenu
authors.forename: Rhys
authors.initials: R
authors.lastname: Christy
authors.forename: Oguz K
authors.initials: OK
authors.lastname: Baskurt
mesh_terms: D000818:Animals; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D019271:Hypoxanthine / Q000494:pharmacology; D008297:Male; D008706:Methemoglobin / Q000378:metabolism; D008773:Methylphenazonium Methosulfate / Q000494:pharmacology*; D018384:Oxidative Stress; D048368:Phascolarctidae; D033081:Shear Strength; D013481:Superoxides / Q000378:metabolism; D004442:Tachyglossidae; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D013481:Superoxides; D008773:Methylphenazonium Methosulfate; D019271:Hypoxanthine; D008706:Methemoglobin; D014969:Xanthine Oxidase