Effects of lead nitrate on histo-cytological alterations of corpuscles of Stannius of stinging catfish, Heteropneustes fossilis

Background: The present study investigated the effects of lead nitrate on the histo-cytological changes in the corpuscles of Stannius (CS) of Heteropneustes fossilis. Methods: Catfish, Heteropneustes fossilis were subjected to 657.6 mg/L and 164.4 mg/L of lead nitrate for 96 h and 28 days, respectively. Blood from fish was collected on 24, 48, 72 and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment. Blood was collected for analysis of calcium levels and CS were fixed for histological studies. Results: Plasma calcium levels of the fish remain unaffected at 24 h. The levels decrease after 48 h which persists till 96 h. Plasma calcium levels of the fish exposed to lead for 7 days exhibit a decrease which persists progressively till 28 days. After 96 h, AF-positive cells of CS exhibit increased granulation. No change in the nuclear volume of these cells has been noticed. An increased nuclear volume has been recorded in the AF-negative cells of CS of 96 h lead exposed fish. After 14 days, the nuclear volume of AF-positive cells decreases. Heavy accumulation of secretory granules and decrease in the nuclear volume of AF-positive cells have been recorded after 21 days which pronounced after 28 days. Moreover, few degenerating cells have also been encountered. AF-negative cells of CS exhibit an increase in the nuclear volume after 21 and 28 days lead treatment. Conclusion: Present findings suggest that exposure of the lead to catfish Heteropneustes fossilis caused CS inactivity .