Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão - Travessa 14 - N 101, Cidade Universitária, CEP 05508-900, São Paulo, SP, Brazil.
Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Campus Diadema, CEP 09972-270, Diadema, SP, Brazil.
Comp Biochem Physiol A Mol Integr Physiol. 2022 Feb;264:111119. doi: 10.1016/j.cbpa.2021.111119. Epub 2021 Nov 16.
Feeding upregulates immune function and the systemic and local (gastrointestinal tract) concentrations of some immunoregulatory hormones, as corticosterone (CORT) and melatonin (MEL), in mammals and anurans. However, little is known about the immune and hormonal regulation in response to feeding in other ectothermic vertebrates, especially snakes, in which the postprandial metabolic changes are pronounced. Here, we investigated the effects feeding have on hormonal and innate immune responses in the snake, Boa constrictor. We divided juvenile males into two groups: fasting and fed with mice (30% of body mass). We measured the rates of oxygen consumption, plasma CORT levels, heterophil/lymphocyte ratio (HL ratio), plasma bacterial killing ability (BKA), and stomach and intestine MEL in fasting snakes and 48 h after meal intake. We observed increased rates of oxygen consumption, plasma CORT levels, and HL ratio, along with a tendency of decreased stomach and intestine MEL in fed snakes compared to fasting ones. BKA was not affected by feeding. Overall, we found that feeding modulates metabolic rates, CORT levels, and immune cell distribution in boas. Increased baseline CORT may be important to mobilize energy to support the metabolic increment during the postprandial period. Increased HL ratio might be an immunoregulatory effect of increased CORT, which has been shown in different physiological situations such as in response to immune challenge. Our results suggest that feeding activates the hypothalamic-pituitary-adrenal axis and modulates immune cell redistribution, possibly contributing to fighting potential injuries and infections derived from predation and from pathogens present in ingested food.
摄食可调节哺乳动物和无尾两栖动物的免疫功能以及一些免疫调节激素（如皮质酮（CORT）和褪黑素（MEL））在全身和局部（胃肠道）的浓度。然而，对于其他变温脊椎动物（尤其是蛇类），人们对其摄食后免疫和激素调节的了解甚少，因为这些动物在摄食后会发生明显的代谢变化。在这里，我们研究了摄食对蟒蛇（Boa constrictor）的激素和先天免疫反应的影响。我们将幼年雄性蟒蛇分为两组：禁食组和喂食组（喂食组用 30%体重的老鼠喂食）。我们测量了摄食后 48 小时内蟒蛇的耗氧率、血浆 CORT 水平、嗜中性粒细胞/淋巴细胞比值（HL 比值）、血浆杀菌能力（BKA）以及胃和肠中的 MEL。与禁食组相比，我们观察到摄食组的耗氧率、血浆 CORT 水平和 HL 比值升高，而胃和肠中的 MEL 则呈下降趋势。BKA 不受摄食的影响。总的来说，我们发现摄食调节了蟒蛇的代谢率、CORT 水平和免疫细胞分布。基础 CORT 水平升高可能对动员能量以支持摄食后代谢增加很重要。HL 比值升高可能是 CORT 升高的免疫调节作用，这种作用在不同的生理情况下都有显示，如对免疫挑战的反应。我们的研究结果表明，摄食激活了下丘脑-垂体-肾上腺轴，并调节了免疫细胞的重新分布，这可能有助于对抗捕食和摄入食物中病原体带来的潜在损伤和感染。
