A scanning electron microscopic probe into the cellular injury in the alimentary canal of Notopterus notopterus (Pallas) after cadmium intoxication.
Microanatomical changes attributable to cadmium poisoning have been observed in the various regions of the alimentary tract of Notopterus notopterus after exposure to sublethal concentrations (75.54 mg CdCl2 liter-1) of the metal. In the buccopharynx, the major changes following treatment with cadmium were shrinkage of the stratified epithelial cells with shriveling of the microridges and loss of lateral contacts between neighboring epithelial cells. But the most pronounced effect was the aggravated secretion of mucin. The damage to the round or oval stratified epithelial cells in the esophagus was manifested by formation of an even sheet of microridges. In the stomach, the most conspicuous changes were the patchy necrosis of the columnar epithelial cells, fragmentation of microridges, and vigorous secretion of mucus from the apical portion of epithelial cells. Owing to cadmium treatment intestinal ceca exhibited disrupted mucosal folds with loss of the normal rectangular box-shaped arrangement. The columnar epithelial cells were found to lose their regular arrangement with an irregular positioning of the microridges within the cells after cadmium exposure. The mucosal folds of the anterior intestine became intensively disrupted with appreciable damage to the columnar epithelial cells. In the middle intestine the surface epithelial cells were adversely torn and the microvilli of the epithelial cells facing the lumen were heavily damaged. After cadmium exposure accelerated mucous cell activity in the intestine was distinct. No conspicuous changes were observed in the rectal portion after cadmium exposure, except for the disintegration of columnar epithelial cells and a concomitant release of large amounts of mucus into the lumen. All these findings suggest impaired digestion and absorption through the alimentary tract of the aforementioned fish.
Ghosh
A R
AR
Zoology Department, Burdwan University, West Bengal, India.
Chakrabarti
P
P
D000818:Animals; D002105:Cadmium Poisoning / Q000473:pathology*; D004064:Digestive System / Q000187:drug effects* / Q000473:pathology; D005399:Fishes; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D007928:Lethal Dose 50; D008855:Microscopy, Electron, Scanning