A histopathological and histochemical study of the osseous and soft tissue in chronic otitis media in rats

Abstract

A histopathological and histochemical study of the osseous and soft tissues in chronic otitis media occuring spontaneously in Wistar rats was made. Histochemical study was confined to localization of enzymatic activities and polysaccharides in the inflammatory lesions. The results obtained were as follows: 1) Histopathology of the chronic otitis media in rats was characterized by marked thickning of the subepithelial layer of the tympanic cavity, in which granulomatous inflammation with infiltration of lymphocytes, plasma cells and pseudoeosinophils was seen, as well as formation of cysts. In the affected bone disappearance of the osteocytes and dilated Haversian canals were found. Although coexistence of osteoblasts and osteoclasts were found in some areas, in general, absorption and degeneration of the bone tissue were predominated. 2) The histochemical distribution of the vari ous enzyme systems in chronic otitis media of rats was investigated.Activities of alkaline phosphatase, ATPase, 5' nucleotidase, lactic dehydrogenase and cytochrome oxidase were demonstrated in the capillaries within the inflammatory granulation tissues of the subepithelial layer of the tympanic cavity. In pseudoeosinophils in the granulation tissue, activities of alkaline phosphatase, ATPase and 5' nueleotidase were noted. Of interest was that epithelium of the cysts, one of the most pronounced findings in chronic otitis media of rats, posessed many enzyme activities including acid phosphatase, ATPase, 5' nucleotidase, succinic dehydrogenase, lactic dehydrogenase, diaphorase, cytochrome oxidase, non-specific esterasecharides were demonstrable. In the periostium, activities of alkaline phosphatase, acid phosphatase, 5' nucleotidase, lactic dehydrogenase, diaphorase and cytochrome oxidase were seen. Although any of the examinated enzyme was not reacted in the bone matrix, the dilated Haversian canals showed the following enzyme activities:Alkaline phosphatase, acid phosphatase, 5' nucleotidase, lactic dehydrogenase, diaphorase, cytochrome oxidase and non-specific esterase. 3) Decalcification by cold 10% solution of EDTA, adjusted to pH 7, 0 with IN NaOH solution after cold aceton fixation of the tissue specimen was recommended for preservation of enzyme activity and polysaccharides in the tissues.