LPS‐induced immunomodulation and hormonal variation over time in toads. Issue 6 (21st May 2021)

• Record Type: Journal Article
• Authors: Titon Junior, Braz; Titon, Stefanny Christie Monteiro; Assis, Vania Regina; Barsotti, Adriana Maria Giorgi; Vasconcelos‐Teixeira, Ronyelle; Fernandes, Pedro Augusto Carlos Magno; Gomes, Fernando Ribeiro
• Is Part Of: Journal of experimental zoology. Volume 335:Issue 6(2021)
• Page Start: 541
• Page End: 551
• Publication Date: 2021-05-21
• Subjects: corticosterone -- ecoimmunology -- inflammatory response -- melatonin -- phagocytosis -- plasma bacterial killing ability; Zoology -- Periodicals; Zoology; Animal Population Groups -- physiology; Zoology; Electronic journals; Periodical; Periodicals; 590
• DOI: 10.1002/jez.2474
• Languages: English
• ISSNs: 2471-5646

Abstract

Abstract: The inflammatory response is a complex process that relies on interactions among multiple endocrine and immune modulators. Studies incorporating time‐related and integrative endocrine and immune responses to an immune challenge might shed light on the characterization of the phases of the inflammatory response in anurans. The present study investigated time‐related changes (1, 3, 6, and 18 h post‐challenge) in plasma corticosterone (CORT), melatonin (MEL) and testosterone (T) levels, phagocytosis percentage (PP), plasma bacterial killing ability (BKA), and neutrophil to lymphocyte ratio (NLR) following a lipopolysaccharide (LPS) immune challenge in Rhinella diptycha toads. Our results showed the response to LPS injection was characterized by increased CORT, PP, BKA, and NLR, with a concomitant decrease in plasma MEL and T. Increased CORT was more pronounced at 6 and 18 h, while increased NLR was observed only 18 h post‐LPS injection. Meanwhile, plasma MEL and T decreased independently of the time post‐LPS injection. Additionally, toads in better body condition showed higher BKA and PP in the LPS‐treated group, regardless of the time postinjection. Our results show that toads ( R. diptycha ) were sensitive to the LPS challenge, mounting an inflammatory response, which started quickly (after 1 h) and developed over time and was influenced by body condition. These results demonstrate a time‐related hormonal and immune variation as a consistent pattern of activation of the immune system, as well as of hypothalamic‐pituitary‐adrenal/interrenal and immune‐pineal axes following an immune challenge more deeply studied in mammals, suggesting the evolutionary conservation of the regulatory mechanisms for tetrapod vertebrates. Abstract : Toads received an intraperitoneal injection of amphibian phosphate‐buffer saline (SAL) or lipopolysaccharides from Escherichia coli (LPS). Toads were injected at 19 h (20 min after lights turned off) and sampled at different time‐points according to years. In 2017: 1 and 6 h after injection (20 and 1 h, respectively); and in 2018: 3, 6, and 18 h after injection (22, 1, and 13 h, respectively). BKA, plasma bacterial killing ability; CORT, plasma corticosterone levels; MEL, plasma melatonin levels; NLR, neutrophil to lymphocyte ratio; PP, phagocytosis percentage; T, plasma testosterone levels. Highlights: Increased CORT, and decreased MEL and T were observed following LPS treatment. LPS increased phagocytosis and BKA within 1 h and 6 h after, respectively. Increased immune redistribution (NLR) was observed 18 h after LPS treatment.