Review of inflammation in fish and value of the zebrafish model

Abstract

Inflammation is a crucial step in the development of chronic diseases in humans. Understanding the inflammation environment and its intrinsic mechanisms when it is produced by harmful stimuli may be a key element in the development of human disease diagnosis. In recent decades, zebrafish (Danio rerio) have been widely used in research, due to their exceptional characteristics, as a model of various human diseases. Interestingly, the mediators released during the inflammatory response of both the immune system and nervous system, after its integration in the hypothalamus, could also facilitate the detection of injury through the register of behavioural changes in the fish. Although there are many studies that give well‐defined information separately on such elements as the recruitment of cells, the release of pro‐ and anti‐inflammatory mediators or the type of neurotransmitters released against different triggers, to the best of our knowledge there are no reviews that put all this knowledge together. In the present review, the main available information on inflammation in zebrafish is presented in order to facilitate knowledge about this important process of innate immunity, as well as the stress responses and behavioural changes derived from it.

Implication of mucus‐secreting cells, acidophilic granulocytes and monocytes/macrophages in the resolution of skin inflammation caused by subcutaneous injection of λ/κ‐carrageenin to gilthead seabream (Sparus aurata) specimens

“…This cytokine, in cooperation with other related mediators (as mentioned above), would be responsible for facilitating leucocyte infiltration to the site of inflammation (Kolaczkowska & Kubes, 2013; Larsen & Henson, 1983; Medzhitov, 2008), which can be observed in the muscle and adjacent connective tissue in samples of skin stained with H&E sampled at 3 hr p.i with carrageenin. In this sense, AGs, which in gilthead seabream are functionally equivalent to mammalian neutrophils (Campos‐Sánchez & Esteban, 2021; Morcillo et al., 2015; Sepulcre et al., 2002), seemed to be the first cells recruited to the inflammation area, given that the quantitative analysis of stained AGs in fish skin was increased firstly at 3 p.i. It could be assumed that this recruitment take place from the blood and ultimately from the head kidney that in teleost is the organ functionally analogous to the mammalian bone marrow.…”

Stages of Granulomatous Response Against Histozoic Metazoan Parasites in Mullets (Osteichthyes: Mugilidae)

“…The chronic inflammatory response is a non-specific reaction against a multitude of factors, such as harmful substances, bacteria, mycobacteria, fungi, and parasites, particularly common in fish [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Chronic inflammation is a complex combination of immune cell action that involves mainly macrophages, epithelioid cells (ECs), fibroblasts, and piscine mast cells (MCs) usually organized as a granulomatous reaction to isolate the pathogens or foreign materials [ 15 , 16 ]. Phagocytosis is a primordial and preserved mechanism of innate immunity in vertebrates, mainly exerted by macrophages, that are considered specialized phagocytes [ 17 , 18 ].…”

Pericardial Injection of Kainic Acid Induces a Chronic Epileptic State in Larval Zebrafish

“…We further investigated inflammatory response upon KA injection by measuring the expression levels of proinflammatory cytokines interleukin 1β ( il1b ), interleukin-8 ( il8 ), and tumor necrosis factor alpha ( tnfa ) as well as fas and interferon regulatory factor 1β ( irf1b ) (Zou and Secombes, 2016 ; Campos-Sanchez and Esteban, 2021 ) in KA-injected larval heads. As early as 3 hpi, the levels of il1b and irf1b were significantly elevated (2.3 ± 0.4 fold change and 5.2 ± 1.5 fold change), and increased even more at 1 dpi together with il8 being more than 3.3 ± 0.7, 3.7 ± 0.6 and 6 ± 1.3-fold higher in comparison to VHC-injected controls, respectively for il1b, il8 and irf1b ( Figure 2E ).…”