Naguib et al. expose African catfish (Clarias gariepinus) to two sizes of silver nanoparticles (20 nm and 40 nm) at two concentrations (10 and 100 µg/L) or to silver nitrate (1.5 mg/L), and document liver enzyme elevation, histopathological changes, and silver accumulation in liver tissue after 15 days, followed by partial recovery after a 15-day clean-water period.
Key numbers
- AgNP exposure concentrations: 10 µg/L and 100 µg/L at 20 nm diameter; 10 µg/L and 100 µg/L at 40 nm diameter; and 1.5 mg/L AgNO3 as ionic silver control (abstract, body text).
- Silver accumulates in liver tissue in all exposed groups relative to controls; liver enzyme concentrations (AST, ALT, ALP) and total lipids and glucose were significantly increased (abstract).
- Histopathological changes at the cellular level: hepatocyte proliferation, inflammatory cell infiltration, pyknotic nuclei, cytoplasmic vacuolation, melanomacrophage aggregation, blood vessel dilation, hepatic necrosis, rupture of central vein wall, and apoptotic cells (abstract).
- Recovery: 15-day clean-water period improved most biochemical and histopathological parameters but did not fully restore them to control levels (abstract).
Methods (brief)
Fish were placed in tanks with water containing the test substance. At the end of 15-day exposure and 15-day recovery periods, blood and liver tissue were collected. Liver Ag concentration was measured by ICP after acid digestion. Histopathology used hematoxylin and eosin staining; glycogen content was assessed by periodic acid Schiff staining. Melanomacrophage centers were quantified morphometrically.
Evidence fitness
Supports documentation of silver nanoparticle hepatotoxicity in a freshwater fish model at concentrations in the environmental range (10 µg/L) to above-environmental range (100 µg/L). This ecotoxicology paper is relevant as context for aquatic hazard assessment of silver nanoparticle releases from food packaging or other sources. It does not measure silver residues in edible fish flesh and does not inform human dietary exposure.
Limitations
Single fish species; laboratory exposure conditions; no measurement of silver in edible muscle tissue that would be consumed. The supra-environmental concentrations used (100 µg/L, 1.5 mg/L) limit direct environmental hazard interpretation. Recovery appears incomplete within the 15-day observation window.
Related evidence
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