Effects of Microcystin-yr containing crude extract on the kidney of freshwater fish Carassius auratus

Abstract

Microcystins (MCs) are known to have detrimental effects on animal health, and their presence in water poses a significant threat to both aquatic animals and humans. In our study, we examined the exposure of Carassius auratus to crude microcystins (containing microcystin-YR) over different time intervals. Fish weighing between 105-120 g were intraperitoneally administered a crude extract containing 200 µg/kg body weight of MC-YR, and the histopathology of kidney tissues was examined at 24- and 48-hours post-dosing. Our findings reveal that the parenchymal architecture of the kidneys was significantly altered by MC-YR. Notably, the structure of pyknotic nuclei began to appear as early as 24 hours post-dosing. The study also observed a flimsy nuclear envelope and distension of vacuoles caused by MC-YR exposure. The catabolism of erythroid tissue in the kidney was exacerbated by an increase in basophilic cells in the epithelial lining, as well as the accumulation of darkly pigmented melanomacrophage aggregates (MMAs) near blood vessels. In conclusion, this study demonstrates that MC-YR, one of the most frequently encountered microcystin variants, has a pronounced impact the kidneys, a secondary target organ, in addition to its primary impact on the liver in fish.