Cadmium Toxicity in Kidney Ultrastructure of Freshwater Fish, Oreochromis mossambicus (Peters)

Kidney is an important organ – vital for excretion, osmoregulation and maintenance of homeostasis; various environmental pollutants like xenobiotics and heavy metals are known to affect its morphology. Fishes can thus act as heavy metal indicators and assess pollution in the aquatic environment. The present work deals with treatment of fishes with cadmium chloride (8ppm for 6days). The changes brought about by cadmium toxicity to the kidney of Oreochromis mossambicus (Peters) was studied using electron microscopy. Light microscopy and ultrastructure of kidney indicates that it consists of 5 distinct regions, namely, neck region, proximal region, central slender region, distal region and collecting tubule. Kidney of cadmium treated fishes show presence of electron dense material within the cytoplasm. Blocking of junctional complex, dilation and fragmentation of endoplasmic reticulum, wavy plasmalemma invaginations, large scale appearance of cytoplasmic vacuoles, occurrence of autophagic vesicles, increased lysosomes, vacuolation/fragmentation of mitochondria are the other changes seen.