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

The present study investigated the effects of lead nitrate on the histo-cytological changes in the corpuscles of Stannius (CS) of Heteropneustes fossilis. 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. 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. Present findings suggest that exposure of the lead to catfish Heteropneustes fossilis caused CS inactivity.