Comparative histological and anatomical biomarkers of the spleen and kidneys in amphibians: a special focus on Rhinella icterica

Abstract

Amphibians belong to a diverse group of ectothermic vertebrates. These animals exhibit a wide range of anatomical and physiological adaptations that allow them to thrive in various aquatic and terrestrial habitats. The spleen and kidneys are two essential organs within the amphibian body. These organs received considerable attention due to their functional significance. The spleen is a component of the lymphatic system, and it is involved in immune responses, hematopoiesis, and erythrocyte turnover. The kidneys, on the other hand, are crucial for maintaining water and electrolyte balance, as well as excretion of metabolic waste products. Understanding the histological and anatomical characteristics of these organs in amphibians is fundamental for gaining insights into their functional capabilities and evolutionary adaptations. The aim of this masters dissertation was to perform two detailed bibliographic reviews, one of them focusing on the spleen, and the other focusing on the kidneys, in amphibians. These reviews will provide a comprehensive synthesis of the existing literature, analyzing the histological and anatomical variations observed across different species, as well as identifying the potential use of these organs as relevant sources of biomarkers for environmental monitoring studies. Here we also present the first detailed description of the histomorphology of the spleen and kidneys in a neotropical anuran species, known as Rhinella icterica. By examining this species in detail, we aim to contribute to the understanding of its physiological and histo-morphological adaptations, and their potential uses in environmental health. Ultimately, this research will contribute to the existing knowledge base on amphibian anatomy and histology, particularly regarding the spleen and kidneys. Our study may have implications for the understanding of amphibian health, disease susceptibility, and conservation efforts. Furthermore, the detailed characterization of the histomorphology of Rhinella icterica will serve as a reference for future comparative studies and may shed light on potential correlations between morphology and function.