Histopathological Changes Induced by Acute Toxicity of Mercuric Chloride on the Air‐breathing Organ (Branchial Diverticulum) of the Live Fish Heteropneustes (= Saccobranchus) fossilis (BLOCH) Histopathologische Veränderungen an den Atmungsorganen des Fisches Heteropneustes (= Saccobranchus) fossilis (BLOCH) aufgrund der akuten Toxizität von Quecksilberchlorid

Abstract

Toxicity induced by 0.3 ppm (96 ppm (96 h LC50 value) mercuric chloride solution on the histomorphology of the innerlining of the air breathing organ (branchial diverticulum) of Heteropneustes fossilis has been described. The outer cell layers of the epithelial lining show cyclic necrosis leading to shedding with ultimate haemorrhage and drainage of blood into the lumen causing decrease in the number of blood islets. Simultaneously the epithelium regenerates causing hyperplasia of its cells and increased gas diffusion distance impairing normal aerial respiration. Also the number of foldings decreases and the secondary lamella like structures fuse together. This results in smoothening of the inner lining of the air sac. Later reappearance of the blood islets, secondary lamellae and foldings of the inner lining are observed along with the repair of the epithelium. Damage of the repaired inner lining follows again. Copyright © 1993 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim