Recovery of damages in the skin of arsenic exposed Clarias batrachus [LINN.] following withdrawal of the stress

The bottom dwelling air-breathing catfish, Clarias batrachus [Linn.] also respires via its skin [an accessory water-breathing organ]. Prolonged [90 days] exposure to disodium arsenate heptahydrate has caused massive damage [e.g. wear and tear of various cellular components including club cells, hypertrophy and hyperplasia of the goblet mucous cells, altered staining and the slimy secretion] to the epidermis of its skin. The present study investigated the recovery in architecture of the damaged epidermis following return of the 90 days disodium arsenate heptahydrate exposed fish to clean water. The significant regeneration of its different cellular components [epithelial cells, Club cells, Mucous cells] took place after 24 h of withdrawal when sloughing; wear and tear and other damages of the epidermis of the skin got substantially reduced. The histopathological alterations which still continued included squeezing out of contents of the Club cells that formed a thin layer on the body surface. Regeneration of the Club cells continued throughout the epidermis even though the newly formed Club cells still showed massive sign of degeneration. Altered staining behaviour and hyperactivity of the Mucous cells continues even after prolonged withdrawal of the stress of the arsenic salt. Similarly the glycoproteins of the slime secreted by the mucous cells retained their sulphate moieties. This indicates that disodium arsenate heptahydrate induces certain permanent non-reversible damages including altered mucogenic activity in the epidermis of the skin of C. batrachus

Toxicopathological impact of sub-lethal concentration of lead nitrate on the aerial respiratory organs of [Murrel] Channa striata [Bloch, Pisces]

Sub-lethal toxicity of lead nitrate solution [46.25mg/L, 5% of 96h LC[50] value] on the air-breathing organ [suprabranchial chamber] of Channa striata was analysed for 60 days. Because air-breathing organs of C. striata remain in direct contact with waterborne xenobiotics, any change in the aquatic ecosystem was directly reflected in them. Concentration of lead accumulation in the air-breathing organ fluctuated at different stages of exposure. Due to extensive secretory activity, the mucous cells very often got exhausted and disappeared followed by their regeneration. This causes periodic fluctuations in the density of the mucous cells. A significant increase in the gross DNA contents in relation to the respective control is noticed at many stages of exposure. Increases in the RNA and protein contents with simultaneous increase in the mucogenic activity of the mucous cells were also observed. The total lipid contents also showed a periodic fluctuation in their concentration