Acute effects of microcystins MC-LR and MC-RR on acid and alkaline phosphatase activities and pathological changes in intraperitoneally exposed tilapia fish (Oreochromis sp.).
Microcystins (MC) are frequently present in cyanobacterial blooms in rivers and lakes, increasing the risk of toxicity to both animals and humans. There more than eighty reported microcystins, and the present study was undertaken to determine whether MC-LR and MC-RR can induce different enzyme alterations and histopathological changes in tilapia fish (Oreochromis sp.) exposed to a single intraperitoneal (i.p.) injection of the pure standards (MC-LR and MC-RR) at a dose of 500 mug/kg; the tilapia fish were then observed for seven days. The two MC variants caused significant changes in the activities of acid and alkaline phosphatases (ACP and ALP) in vital organs, showing a different response pattern. The livers and kidneys of fish injected with MC-LR were particularly affected. MC-RR induced a very pronounced increase of ACP in the kidney and a significant increase of ALP in the liver. Both MC variants caused pathological lesions in hepatic tissues, such as megalocytosis, necrotic process, and microvesicular steatosis, particularly in fish treated with MC-LR, and degenerative renal changes, glomerulopathy, were more severe in tilapias exposed to MC-RR. In addition, both microcystins also caused significant myopathy in the heart. In contrast, the gills did not show any change in enzyme activity or histopathological injury.
Atencio
Loyda
L
Area de Toxicología, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain.
Moreno
Isabel
I
Prieto
Ana I
AI
Moyano
Rosario
R
Molina
Ana M
AM
Cameán
Ana M
AM
D000135:Acid Phosphatase / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D056486:Chemical and Drug Induced Liver Injury; D023681:Cichlids; D005880:Gills / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D006321:Heart / Q000187:drug effects; D007274:Injections, Intraperitoneal; D007668:Kidney / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D007674:Kidney Diseases / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008107:Liver Diseases / Q000201:enzymology / Q000473:pathology; D052998:Microcystins / Q000633:toxicity*; D009206:Myocardium / Q000473:pathology; D009929:Organ Size / Q000187:drug effects
D001427:Bacterial Toxins; D052998:Microcystins; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase