Melanomacrophage functions in the liver of the caecilian Siphonops annulatus

Abstract

Melanomacrophages are phagocytes that synthesize melanin. They are found in the liver and spleen of ectothermic vertebrates, and in the kidney of fish. In agnathan and elasmobranch fish, melanomacrophages are seen as isolated cells, and forming clusters in all the other vertebrates. The natural phagocytic activity of melanomacrophages is poorly characterized, as most of the research works have focused on induced phagocytic activity only. Furthermore, little is known about amphibian melanomacrophages, mainly about those in caecilians - wormlike amphibians in the order of Gymnophiona, which is the least known group of terrestrial vertebrates. The present research work aimed at the structure and function of hepatic melanomacrophages of Siphonops annulatus, a species largely found in South America. We identified the role of these cells in the control of circulating basophils (pro-melanogenic cells), in the turnover of liver collagen stroma and in the hemocatheresis, interrelated physiological mechanisms.

Idiosyncratic liver pigment alterations of five frog species in response to contrasting land use patterns in the Brazilian Cerrado

“…Morphofunctional changes in the hepatic parenchyma happen as a result of contaminants, suggesting the action of detoxification by MMs due to the processing action of some enzymes, besides the protective action of melanin (Fenoglio et al, 2005). Additionally, the functions of MMs are also related to the maintenance of homeostasis, regulating fibrosis, controlling basophiles, and participating in the recycling of red blood cells (Gutierre et al, 2018).…”

Liver description in three neotropical anuran species: from anatomy to ultrastructure

“…On the other hand, Gutierre et al. (2018) described a double cord in Siphonops annulatus Mikan, 1822, while Muikham et al. (2017) described the same pattern for Ichthyophis supachaii Taylor, 1960, both belonging to Gymnophiona order.…”

Hepatotoxicity and Nephrotoxicity of Lead Nitrate in Toad Bufo viridis

“…Melanomacrophage centers are Melanophores exist mainly in the liver, kidney and spleen of fish (Agius and Roberts, 2003), frog and toad (Steinel and Bolnick, 2017). They are phagocytes that synthesize melanin (Gutierre et al, 2018). These cells respond to catabolism processes (Kalashnikova, 2000, Steinel andBolnick, 2017), immunological disorders (Pronina et al, 2014, Steinel andBolnick, 2017) , Uv Uv exposure (Franco-Belussi et al, 2016) and hibernation (Barni et al, 2002).…”