Systemic polyhydroxylated fullerene toxicity in fathead minnows (Pimephales promelas Rafinesque, 1820)

Abstract

Carbon nanoparticles have the potential to serve as nanopharmaceutical delivery systems for drugs, genes, and immunogens. They are able to both generate and scavenge reactive oxygen species (ROS) and, like some other nanomaterials, may induce autophagy. Controversy exists regarding their potential for toxicity. Systemic administration of hydroxylated fullerene nanoparticles to fish has been reported to result in renal accumulation and nephropathy, as well as impairment of innate immune responses. To better characterize biocompatibility and the potential for adverse systemic effects, we administered the water soluble fullerenol, C60(OH)24, to fathead minnows (Pimephales promelas), a model organism for environmental toxicology studies. Briefly, adult minnows were injected intraperitoneally with 20 micrograms/g, the lowest lethal dose observed in a preliminary study. Fish died or were euthanized moribund within 36 hours post‐injection. Sections of whole fish from control and treatment groups were evaluated using a four‐category scoring system comprising 31 different histologic features. Statistically significant tissue changes were observed in the kidney and sensory system and included renal edema, degeneration of tubular epithelium, pigment accumulation and loss of hematopoietic tissue in the trunk kidney and degeneration or death of ciliated sensory cells in the ear. Investigation into cellular and molecular mechanisms associated with these morphologic changes may provide valuable information to direct development of safe fullerene‐based delivery systems. This work was supported by the Iowa State University Office of the Vice President for Research.