Rodlet cells in teleosts: a new insight into their nature and functions

Abstract

The nature of rodlet cells (RCs) and their functions is subject to a number of different interpretations. This review provides a detailed analysis of the parasitic and endogenous origin of these cells. Two new functional aspects of RCs are considered in detail. The possible function of RCs as immune cells was derived from studies that reported an increase in the number of RCs in fish infected with protozoan and metazoan parasites, particularly at the site of the pathogen infection and/or attachment. Accordingly, RCs represent inflammatory cells, with a similar role to eosinophile granule cells, epithelioid cells and mesothelial cells. Rodlet cells may potentially act as biomarkers. Experimental studies that examined the response of RCs in fish exposed to chemical substances such as metals and herbicides reported an increase in the number of RCs in the tissues of the fish. Fish exposed to these substances expressed myelinic figures in the cytoplasm of the RCs and various degrees of rodlet degeneration and high vacuolization of RC cytoplasm were often noticed. Further lines of research are suggested that might elucidate the true function of these enigmatic cells. # 2004 The Fisheries Society of the British Isles

Histopathological and ultrastructural observations of metacercarial infections of Diplostomum phoxini (Digenea) in the brain of minnows Phoxinus phoxinus

“…It is believed that rodlet cells play a role within the piscine inflammatory response (Dezfuli et al 2000, Manera & Dezfuli 2004, Reite 2005, Reite & Evensen 2006. We found rodlet cells only within the infected brain of a fish, and our findings are briefly compared with the information available on their presence in other fishparasite systems (Dezfuli et al 1998, 2000, 2002, Reite 1998, Bosi et al 2005.…”

“…Rodlet cells are, as far as we are aware, exclusive to fish and are associated with the epithelial tissues of virtually every fish species (Morrison & Odense 1978). Recent research by a number of workers lends support to the theory that rodlet cells have an endogenous fish origin (Manera & Dezfuli 2004, Giari et al 2006, Reite & Evensen 2006, Dezfuli et al 2007. Although their precise function is unknown, it is thought that rodlet cells are a type of inflammatory cell akin to other piscine inflammatory cells (e.g.…”

Anatomia e histologia gastrintestinal da garoupa-verdadeira Epinephelus marginatus (Lowe, 1834) (Teleostei, Serranidae)

“…Nos intestinos anteriores e médios foram identificadas células que apresentavam inclusões citoplasmáticas na forma de bastões, as quais são descritas na literatura como células bastonetes rodlet cells (MANERA;DEZFULI, 2004) As descrições referentes à histologia do reto de E. marginatus são contrárias às encontradas na literatura referente a teleósteos (HIBIYA, 1982), as quais citam uma submucosa pobremente vascularizada, o que não ocorre nessa espécie, cuja mucosa era bem irrigada.…”

The effect of hypoxia on gill morphology and ionoregulatory status in the Lake Qinghai scaleless carp, Gymnocypris przewalskii

“…In a number of teleost fish, the gill epithelium contains rodlet cells (RCs), however, their origin and function remain unknown. They have been proposed to act as non-specific immune cells (Manera and Dezfuli, 2004) or have a secretory function based upon the presence of rodlet granules rich in glycoproteins and carbohydrates that are released on the epithelial surface (Leino, 1982;Leino, 2001;Matey, 1996).…”