Prasad M S
Department of Zoology, Bihar University, Muzaffarpur, India.
Biomed Environ Sci. 1994 Dec;7(4):337-45.
Alterations in the respiratory epithelium of gills of a catfish, Heteropneustes fossilis by the sublethal and lethal concentrations of HgCl2 have been observed using scanning electron microscope. Fish exposed to 0.1 ppm shows a thin coat of mucus, but the continuous layer of mucus is not retained in 0.3 ppm after 24 h of exposure. Epithelial cells of the gill filament are hyperplastic. Other changes in the respiratory epithelium are contraction of epithelium, formation of interlamellar bridge and diminishing number of microridges. Massive destruction of the respiratory epithelium by deep lesions and sloughing of epithelial layer in 0.5 and 1.0 ppm solutions after 6-12 h of exposure apparently causes death to the fish. SEM observations are well in conformity with the findings made at light microscopic level.
利用扫描电子显微镜观察了HgCl₂的亚致死浓度和致死浓度对鲶鱼（Heteropneustes fossilis）鳃呼吸上皮的影响。暴露于0.1 ppm HgCl₂的鱼显示出一层薄薄的黏液，但暴露24小时后，0.3 ppm浓度下的连续黏液层无法保留。鳃丝的上皮细胞增生。呼吸上皮的其他变化包括上皮收缩、片层间桥的形成以及微嵴数量的减少。暴露6 - 12小时后，0.5 ppm和1.0 ppm溶液中呼吸上皮因深层损伤和上皮层脱落而遭到大量破坏，显然导致鱼死亡。扫描电子显微镜观察结果与光学显微镜水平的发现完全一致。
