Simmonds Michael J, Meiselman Herbert J, Marshall-Gradisnik Sonya M, Pyne Michael, Kakanis Michael, Keane James, Brenu Ekua, Christy Rhys, Baskurt Oguz K
Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia.
Biorheology. 2011;48(5):293-304. doi: 10.3233/BIR-2012-0599.
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.
本研究旨在根据细胞变形性的变化，研究四种物种（针鼹、人类、考拉、袋獾）红细胞（RBC）的氧化应激敏感性。选择这些物种是基于与不同氧化应激水平相关的生活方式和/或生物学差异。主要重点是细胞内产生的超氧自由基（吩嗪硫酸甲酯，PMS，50μM）或细胞外介质中产生的超氧自由基（黄嘌呤氧化酶-次黄嘌呤，XO-HX，0.1 U/ml XO）对不同剪切应力（SS）下RBC变形性的影响。使用“狭缝流动血细胞分析仪”通过激光衍射分析评估RBC变形性。两种产生超氧自由基的处理均导致所有物种的高铁血红蛋白显著增加（p<0.01），袋獾RBC对两种处理表现出最高的敏感性。PMS导致所有物种的RBC变形性受损，但观察到种间存在巨大差异：人类和考拉细胞对SS表现出类似的S形反应，短喙针鼹的值明显较低，且随SS仅略有增加，而袋獾RBC则极其僵硬。与PMS相比，XO-HX对RBC变形性的影响较小（即刚性增加较小），但袋獾RBC除外，即使在最高SS下也基本不发生变形；因此，袋獾RBC对XO-HX的反应与PMS观察到的反应相当。我们的研究结果表明，血细胞分析仪可用于确定不同物种RBC的氧化应激敏感性，这在代表不同生活方式和进化历史的哺乳动物之间存在显著差异。这些敏感性差异与观察到的和根据异速生长预测的寿命之间的物种特异性差异一致，并且与衰老的氧化应激理论相符。
