Histopathological alterations in the gill and kidney of an estuarine mullet, Liza parsia (Hamilton-Buchanan), caused by sublethal exposure to lead (Pb)

Abstract

In order to assess the effects of lead (Pb) on gill and kidney of an estuarine fish, Liza parsia the fish was exposed to sublethal concentration (0.5 ppm) of lead nitrate in sea water for 15 days. Gill responded initially with an enhanced secretion of mucus and oedematous separation of the epithelial lining cells from the basement membrane of the secondary gill lamellae. Hyperplasia, multiple telangiectases (aneurysms), desquamation of the epithelial cells, complete fusion of secondary gill lamellae and congestion of blood sinuses were the significant histopathological lesions observed in the gill during the period of observation. The entire interlamellar spaces became filled with the hyperplastic epithelium by day 15 of Pb exposure. Trunk kidney of the treated fish revealed initial hypertrophy and vacuolation of the epithelial cells lining, proximal convoluted tubules and shrinkage in the glomeruli resulting in dilation of Bowman's space on day 4. Necrotic changes like oedema, pycnosis, karyorrhexis, karyolysis, cytolysis and fibrosis were observed in the kidney of the fish exposed to Pb intoxication.