ABSTRACT
Cadmium is an important metal for modern industrial processes and, being biologically non-essential, poses health hazards to the organisms. In this study we aimed to evaluate the effect of cadmium exposure on the histo-cytology of prolactin cells in the freshwater catfish, Heteropneustes (H.) fossilis. Fish were subjected to 288 mg/L (0.8 of 96 h LC50) and 72 mg/L (0.2 of 96 h LC50) of cadmium chloride for short-term and long-term, respectively. After sacrificing the fish, the blood was collected on 24, 48, 72 and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment and analyzed for plasma calcium levels. Also, pituitary glands were fixed on these intervals. The plasma calcium levels of short-term cadmium exposed fish remain unchanged after 24 h. The levels exhibit a progressive decrease from 48 h onwards. The fish exposed to cadmium for 7 days exhibit a decrease in the plasma calcium level. Thereafter, the levels progressively decrease till the end of the experiment (28 days). The prolactin cells of the control fish exhibit structural resemblance to the description given for the prolactin cells of normal H. fossilis. No change in the histological structure and nuclear volume of prolactin cells of cadmium non-exposed fish has been noticed throughout the experiment. In cadmium treated fish, the prolactin cells remain unchanged till 14 days. On day 21, the nuclear volume of these cells exhibits an increase and the cells degranulate. These changes increased profoundly on day 28. In addition, vacuolization and cytolysis were also encountered on day 28 following cadmium treatment. It is concluded that cadmium affects the prolactin cells of the fish H. fossilis thus disturbing the ionic balance.
El cadmio es un metal importante para los procesos industriales modernos, siendo no esencial biológicamente, representa riesgos para la salud de organismos. En este estudio tratamos de evaluar el efecto de la exposición al cadmio por el aspecto histológico y citológico de células secretoras de prolactinas del pez gato de agua dulce Heteropneustes (H.) fossilis. Los peces fueron sometidos a una exposición de 288 mg/L (0,8 de 96 h CL50) and 72 mg/L (0,2 de 96 h CL50) de cloruro de cadmio por a corto y largo término respectivamente. Después del sacrificio de los peces, la sangre fue colectada, tomando muestras de 24, 48, 72 y 96 hs en el corto término y de 7, 14, 21 y 28 días en las sometidas a largo término, la cuales se analizaron para medir niveles de calcio. Además, las glándulas pituitarias fueron fijadas en esos intervalos El nivel plasmático de calcio en los experimentos de exposición a corto tiempo se mantuvo sin cambio tras 24 h. Los niveles exhibieron una caída progresiva a partir de las 48 hs. Los peces expuestos a cadmio por 7 días presentaron una disminución en el nivel plasmático de calcio. Después de esto, los niveles decayeron progresivamente hasta el fin del experimento (28 días). Las células prolactínicas de los peces controles mostraron semejanza estructural a la descripción dada para estas células normales en H. fossilis. No se observaron cambios en la estructura histológica y el volumen nuclear de las células prolactínicas de los peces no expuestos a cadmio a través de todo el experimento. En los peces tratados con cadmio las células prolactínicas se mantuvieron sin cambios hasta los 14 días. En el día 21, el volumen nuclear de esas células se incrementó y estas células presentaron desgranulación. Estos cambios aumentaron profundamente en las muestras del día 28. Adicionalmente en el día 28 posterior al tratamiento con cadmio se encontró vacuolización y citólisis. Se concluyó en que el Cadmo afecta las cñelupas prolactínicas de H fossilis, produciendo disturbios en el balance iónico.
Subject(s)
Animals , Cadmium Poisoning/blood , Cadmium Poisoning/diagnosis , Catfishes/anatomy & histology , Prolactin/analysisABSTRACT
Freshwater fish Heteropneustes fossilis (H. fossilis) were subjected to 5.76 µg/L (80% of 96 h LC(50) ) and 1.44 µg/L (20% of 96 h LC(50) ) of cypermethrin for short-term (96 h) and long-term (28 days) duration, respectively. Plasma calcium of H. fossilis exposed for short term (96 h) to cypermethrin exhibited no change at 24 h. The levels indicate a decrease in plasma calcium at 48 h. This response persists till the close of experiment (96 h). No change has been noticed throughout the experiment in the histological structure and nuclear volume of prolactin cells of short-term cypermethrin treated fish. Long-term exposure of cypermethrin to fish provoked hypocalcemia. The prolactin cells remain unchanged till 7 days following cypermethrin treatment. After 14 days, the nuclear volume exhibits an increase and the cells exhibit degranulation. These changes increase progressively 21 days onwards. Also, few degenerating cells are discerned after 28 days.
Subject(s)
Catfishes/physiology , Insecticides/toxicity , Lactotrophs/drug effects , Prolactin/blood , Pyrethrins/toxicity , Animals , Calcium/blood , Dose-Response Relationship, Drug , Lactotrophs/metabolism , Lactotrophs/pathology , Lethal Dose 50 , Water Pollutants, Chemical/toxicityABSTRACT
Heteropneustes fossilis were subjected to 288 mg/L (0.8 of 96 h LC(50)) and 72 mg/L (0.2 of 96 h LC(50)) of cadmium chloride for short-term and long-term experiments, respectively. After sacrificing the fish, the blood was collected on 24, 48, 72, and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment and analyzed for plasma calcium levels. Also, ultimobranchial glands were fixed on these intervals. The plasma calcium levels of short-term cadmium-exposed fish remain unchanged after 24 h. The levels exhibit a progressive decrease from 48 h onwards. The fish exposed to cadmium for 7 days exhibit a decrease in the plasma calcium level. Thereafter, the levels progressively decrease till the end of the experiment (28 days). Up to 72 h exposure of the fish to cadmium, the ultimobranchial gland exhibits no histological change. After 96 h, a decrease in the staining response of the cytoplasm of ultimobranchial cells has been noticed. The nuclear volume of these cells records a slight decrease. Up to 14 days of cadmium exposure, there is no change in the histological structure of ultimobranchial gland. After 21 days following the exposure, the ultimobranchial cells exhibit a slight decrease in the staining response of the cytoplasm and the nuclear volume of these cells records a decrease. Following 28 days cadmium exposure the nuclear volume exhibits a further decrease, and degeneration and vacuolization sets in.
