Falso Paul G, Noble Christopher A, Diaz Jesus M, Hayes Tyrone B
Department of Biology, Slippery Rock University, Slippery Rock, PA 16057, USA.
Laboratory for Integrative Studies in Amphibian Biology, Molecular Toxicology Group, and Integrative Biology Department, University of California, Berkeley, CA 94720-3140, USA.
Gen Comp Endocrinol. 2015 Feb 1;212:73-83. doi: 10.1016/j.ygcen.2015.01.003. Epub 2015 Jan 20.
The effect of long-term stress on amphibian immunity is not well understood. We modeled a long-term endocrine stress scenario by elevating plasma corticosterone in two species of amphibians and examined effects on white blood cell differentials and innate immune activity. Plasma corticosterone was elevated in American bullfrogs (Lithobates catesbeianus) by surgically implanting corticosterone capsules and in African clawed frogs (Xenopus laevis) by immersion in corticosterone-treated water. To provide a context for our results within endogenous corticosterone fluctuations, diurnal plasma corticosterone cycles were determined. A daily low of corticosterone was observed in X. laevis at 12:00, while a significant pattern was not observed in L. catesbeianus. Elevated plasma corticosterone levels increased the ratio of peripheral neutrophils to lymphocytes, in both species, and decreased eosinophil concentrations in L. catesbeianus over a long-term period. Whole blood oxidative burst generally correlated with neutrophil concentrations, and thus was increased with corticosterone treatment, significantly in L. catesbeianus. In L. catesbeianus, an endogenous response of eosinophils and lymphocytes to implanted empty (sham) capsules was observed, but this effect was attenuated by corticosterone. Peripheral monocyte and basophil concentrations were not significantly altered by corticosterone treatment in either species. Our results show that long-term stress can alter amphibian immune parameters for extended periods and may play a role in susceptibility to disease.
长期应激对两栖动物免疫力的影响尚未得到充分了解。我们通过提高两种两栖动物的血浆皮质酮水平，模拟了一种长期内分泌应激情况，并研究了其对白细胞分类和先天免疫活性的影响。在美国牛蛙（牛蛙）中，通过手术植入皮质酮胶囊来提高血浆皮质酮水平；在非洲爪蟾（非洲爪蟾）中，则通过浸泡在经皮质酮处理的水中来提高血浆皮质酮水平。为了在体内皮质酮波动的背景下理解我们的结果，我们测定了昼夜血浆皮质酮循环。在非洲爪蟾中，观察到皮质酮在12:00出现每日低点，而在牛蛙中未观察到明显的模式。长期来看，两种物种中血浆皮质酮水平的升高均增加了外周中性粒细胞与淋巴细胞的比例，且在牛蛙中降低了嗜酸性粒细胞浓度。全血氧化爆发通常与中性粒细胞浓度相关，因此经皮质酮处理后增加，在牛蛙中尤为显著。在牛蛙中，观察到嗜酸性粒细胞和淋巴细胞对植入的空（假）胶囊有内源性反应，但这种效应被皮质酮减弱。两种物种中，皮质酮处理均未显著改变外周单核细胞和嗜碱性粒细胞浓度。我们的结果表明，长期应激可在较长时间内改变两栖动物的免疫参数，并可能在疾病易感性中起作用。
