Reticulin morphometry and collagen fibers optical anisotropy as assessed by image analysis after silver impregnation

RESUMO

A new method for the impregnation of tissue sections with ammoniacal silver carbonate in terms of single-step reaction, no gold toning, no oxidation step and silver impregnation after treatment with pancreatic (alfa)-amylase is described. This method yields silver nanocrystalloids with 18.40 nm in average diameter [16]. Natural carbohydrate radicals probably acting as natural reducing agents for silver are assumed to occur. Despite the fact that the method is not specific, reticulin fibers (type III colagen) were clearly distinguished from other collagen fibers types and easily and accurately segmented by image analysis (IA) systems, when using this procedure. Data from myocardial reticulin fibers are presented. Collagen bundles (type I collagen rich structures) exhibited intense linear dichroism (LD) interms of gray averages measured by IA (non-impregnated, natural, collagen fibers do not show LD) Anomalous dispersion of birefringence was also detected, highlighting typical morphologies, including crimp, which allow us to propose the methodo for molecular order studies and to assess collagen bundles as chiral objects, especially together with LD data.