Liver Histopathologic Alterations in the Frog Rana ridibunda from a Small River of Northern Greece

Abstract

The various histopathologic alterations detected in the liver of the frog Rana ridibunda from a small river of Northern Greece were investigated. In the livers of the frogs collected from this river, there was an increase in the area occupied by melanomacrophages as well as an increase in their color intensity. Mild karyomegaly and polyploidy, together with solitary and focal accumulation of infiltrates (neutrophils and lymphocytes), was evident. Three different kinds of foci were detected basophilic focus, vacuolated focus, and a special type of focus with nodules surrounded by collagen. Some bile ducts were found to be filled with periodic acid schiff (PAS)-positive amorphous material mixed with cellular debris. In liver foci of dense connective tissue, with structures resembling bile ductuli, were detected. The latter finding supports the conclusion that this might be early holangiofibroma. Progressive fibrosis around bile ducts, which extended into the hepatic parenchyma, was obvious. Given that the river under study was previously characterized as being moderately to heavily polluted, it was concluded that a number of environmental factors, including heavy metals, might be responsible for these histopathologic alterations.

Liver histology and ultrastructure of the Italian newt (Lissotriton italicus): Normal structure and modifications after acute exposure to nonylphenol ethoxylates

“…A similar increase has been reported in amphibians under both physiological or pathological conditions, such as exposure to low temperatures, oxygen deficit, infectious diseases, starvation, and exposure to heavy metals and other contaminants (Wolke, 1992;Barni et al, 1999;Frangioni et al, 2000;Loumbourdis and Vogiatzis, 2002;Fenoglio et al, 2005;Silva et al, 2013). In amphibians and other vertebrates, the melanin of the liver pigment cells seems to play an important role as scavengers of cytotoxic substances such as reactive oxygen species (ROS) or other toxic substances (Bustamante et al, 1993;Rozanowska et al, 1999;Loumbourdis, 2007). In particular, it has been hypothesized that in amphibians melanin may represent a valid alternative to enzymes involved in the detoxification, replacing the antioxidant activity of both superoxide dismutase (SOD) and glutathione (GSH) (Sichel et al, 1987;Geremia et al, 1989).…”

Melanomacrophage functions in the liver of the caecilian Siphonops annulatus

“…Other studies have shown phagocytic activity of melanomacrophages in the liver of amphibians living in polluted areas (Fenoglio et al. ; Loumbourdis ), and evidenced hemocatheresis by staining precipitated hemosiderin with Perls stain (Fenoglio et al. ).…”

“…; Fenoglio et al. ; Loumbourdis ). The ultrastructural study also demonstrated this parallel, showing a melanomacrophage and its membrane extensions engulfing two cells.…”

“…These studies could help with the fact that the population of amphibians has been decreasing dramatically over the last past years due to the pollution of the environment, mainly due to water pollution (Fenoglio et al. ; Loumbourdis ). Because the liver plays a major role in biotransformation occurring in the body by means of the functioning of its phagocytes and hepatocytes (Fenoglio et al.…”

“…Because the liver plays a major role in biotransformation occurring in the body by means of the functioning of its phagocytes and hepatocytes (Fenoglio et al. ; Loumbourdis ), the understanding of the roles of the cells in the hepatic tissue, especially those of melanomacrophages or Kupffer cells, and their interactions with the other cells is of great importance.…”