The Use of Texture Analysis in the Morpho-Functional Characterization of Mast Cell Degranulation in Rainbow Trout (Onchorhynchus mykiss)

Abstract Degranulation of intestinal mast cells in rainbow trout was studied ex vivo by means of texture analysis and related to the maximal intestinal contraction elicited by degranulation itself. Two strips from the same intestinal segment from ten trout were sampled, processed for light microscopy and stained with Giemsa solution. One of the two strips was exposed to an incremental dose of compound 48/80 in an isolated organ bath before processing. Gray-level RGB channel equivalent and 8-bit gray-level images of five granular cytoplasm areas of mast cells for each section were analyzed for texture features and to evaluate discrimination possibility between treatment groups by means of linear discriminant analysis according to feature selection methods and RGB stacks. Differential mean values (after–before compound 48/80) of the green (r² = 0.84, p < 0.01) and blue (r² = 0.83, p < 0.01) RGB channels and 8-bit grayscale (r² = 0.76, p < 0.05) image correlated significantly with the respective value of maximal intestinal contraction. A possible acidic (anionic) nature for the putative pro-contractile basophil agonist can be inferred.