Selective staining and disintegration of intestinal eosinophilic granule cells in Atlantic salmon after intraperitoneal injection of the zinc chelator dithizone

• Published in: Journal of Fish Biology
• Main Authors: Paulsen, S. M., Sveinbjørnsson, B., Robertsen, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2001.tb00529.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2001.tb00529.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2001.tb00529.x

Following intraperitoneal injection of the zinc ion chelator dithizone into Atlantic salmon Salmo salar , staining and morphological changes in intestinal eosinophiic granule cells (EGC) were observed in both cryo‐preserved and chemical‐preserved tissue sections. In cryo sections rapid and selective vital staining of EGC was observed within 5 min of dithizone injection. Intensely stained red granules appeared as a result of the formation of a complex between dithizone and zinc ions. Stained EGC appeared on both sides of the stratum compactum as well as in the lamina propria . Stained EGC started to disintegrate 5 min after the injection of dithizone, and little of the zinc‐dithizone complex was observed 15 h later. The disappearance of the stain coincided with an intense degranulation and disintegration of EGC. Fifteen hours after dithizone treatment regenerating cells were observed in Masson's trichrome stained sections. Four to five days after injection, a fully regenerated continuous EGC layer was observed. Simultaneously with the disintegration of EGC an increase in plasma lysozyme activity occurred. EGC resembles mammalian Paneth cells in their possession of lysozymecontaining granules and their staining by, and response to, dithizone. EGC may represent a central component of zinc metabolism in Atlantic salmon.