SIGNALMENT: (age, breed, sex, species, and scientific name)
~3 month-old male Fischer 344 rat.
Animals were treated once daily with 50 mg acrylamide/kg body weight by i.p. injection. All rats lost body weight within the first few days and developed varying severity of hind-limb paresis and ataxia. The acrylamide dose was reduced to 30 mg/kg after day 4, and injections were discontinued after day 8. Animals were killed on day 11 by an i.p. injection of pentobarbital and whole-body perfusion with buffered 4% paraformaldehyde via a cannula in the ascending aorta. Tissues were routinely processed, sectioned, and stained with hematoxylin and eosin (images are all from the same animal).
Testes were small and pale. Epididymides were reddened.
Acrylamide was used to induce lesions for positive-control neuropathology in accordance with the EPA’s Tier 2 regulations on toxicology of engine emissions from testing fuels and fuel additives (40 CFR, Part 79.66(e)(3)). Cerebellar lesions consisting of granular layer cell degeneration and Purkinje cell necrosis have been described previously in acrylamide-treated rats (Abou-Donia et al., 1993).
Short-term administration of acrylamide has been shown to selectively affect round spermatids in stages I-III in the mouse testis (Sakamoto et al., 1988), but published histopathology of testicular lesions in rats that have been induced by acrylamide or acrylamide derivatives is lacking. Analysis of specific lesions of reproductive toxicity in the rat was not the purpose of the current study. Aside from the generalized degeneration of seminiferous tubules depicted here, other acrylamide-intoxicated rats displayed testicular changes ranging from mild multifocal tubular degeneration to marked locally extensive necrosis and hemorrhage. A time-course and dose-response study would be necessary for a better understanding of the pathogenesis of these lesions.
Sakamoto, J., Kurosaka, Y., Hashimoto, K. (1988) Histological changes of acrylamide-induced testicular lesions in mice. Exp. Mol. Pathol.; 48(3): 324-334.
10X H&E. Cerebellum from a rat treated with acrylamide. Note Purkinje cell hypereosinophilia and nuclear pyknosis. Vacuolar change, nuclear condensation, and pyknosis are present in cells of the granular layer.
40X H&E. Cerebellum from a rat treated with acrylamide. The higher magnification shows nuclear fragments scattered in the granular cell layer.