Abstract

During adaptation to a semi-aquatic lifestyle, the muskrat (Ondatra zibethicus) developed numerous biochemical adaptations to maintain oxygen homeostasis. The aim of the study was to explore age-related and seasonal changes in muscle tissue antioxidant defenses and erythrocyte morphometric parameters in the muskrat. Animals were captured in autumn (juveniles and adults) and spring (adults) in the North-West of Russia (Republic of Karelia). Some physiological and biochemical parameters of “autumn” animals showed an age-related variability: in adult muskrats (most adapted to diving), as compared to juveniles, catalase activity in skeletal muscles was lower, while the respiratory function of blood was higher (due to a lower total surface area of erythrocytes). Adult muskrats demonstrated seasonal changes in some parameters: in “spring” animals, activities of catalase in the heart and superoxide dismutase in skeletal muscles were higher, while levels of low-molecular-weight antioxidants (α-tocopherol and glutathione) both in cardiac and skeletal muscles were lower compared to “autumn” animals. After a long winter (ice-fishing) season, the blood of “spring” animals contained mainly mature erythrocyte forms (normocytes), with their average diameter and surface area being larger than in adult “autumn” muskrats. Our findings, as well as data obtained on other species, support the involvement of the antioxidant system and erythrocytes in the mechanisms that maintain oxygen homeostasis in diving mammals.

中文翻译：

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麝香Ondatra zibethicus的肌肉抗氧化防御和红细胞形态学参数的年龄相关和季节性变化

摘要

在适应半水生生活方式时，麝香（Ondatra zibethicus）开发了许多生化适应方法来维持氧稳态。该研究的目的是探讨麝香鼠中肌肉组织抗氧化防御系统和红细胞形态参数的年龄相关和季节性变化。在俄罗斯西北部（卡累利阿共和国）的秋天（青少年和成人）和春天（成人）捕获了动物。“秋季”动物的某些生理和生化参数显示出与年龄相关的可变性：成年麝香（最适合潜水）与幼稚相比，骨骼肌中的过氧化氢酶活性较低，而血液的呼吸功能较高（由于至较低的红细胞总表面积）。成年麝香在某些参数上表现出季节性变化：在“春季”动物中，与“秋季”动物相比，心脏和骨骼肌中过氧化氢酶的活性较高，骨骼肌中的超氧化物歧化酶较高，而心脏和骨骼肌中的低分子量抗氧化剂（α-生育酚和谷胱甘肽）的水平较低。经过漫长的冬季（冰钓）季节之后，“春季”动物的血液主要含有成熟的红细胞形式（正常细胞），其平均直径和表面积大于成年“秋天”麝香鼠。我们的发现以及其他物种的数据支持了抗氧化系统和红细胞参与了维持潜水哺乳动物的氧气稳态的机制。经过漫长的冬季（冰钓）季节之后，“春季”动物的血液主要含有成熟的红细胞形式（正常细胞），其平均直径和表面积大于成年“秋天”麝香鼠。我们的发现以及其他物种的数据支持了抗氧化系统和红细胞参与了维持潜水哺乳动物的氧气稳态的机制。经过漫长的冬季（冰钓）季节之后，“春季”动物的血液主要含有成熟的红细胞形式（正常细胞），其平均直径和表面积大于成年“秋天”麝香鼠。我们的发现以及其他物种的数据支持了抗氧化系统和红细胞参与了维持潜水哺乳动物的氧气稳态的机制。