Effect of acrylamide on the central nervous system of rates: histological, histochemical, and electron microscopy studies

ABSTRACT

The effect of acrylamide on the central nervous system of rats was studied in order to determine its neurotoxicity effect. Seventy rats were used in the present study which were divided into three groups. The rats of group one were used as control while rats of group two were given acrylamide by intramuscular injection with a dose of 5 mg/kg body weight, and the rats of group three were given 25 mg/kg acrylamide twice weekly for one month. The rats were sacrificed after 1, 2, 3, and 4 weeks of acrylamide injection and cervical spinal cord was removed and processed for histological, histochemical, and electron microscopical studies. Histological results showed mild degenerative changes of nerve fibers after one and two weeks of acrylamide injection while after three and four weeks severe changes were seen following both doses of acrylamide. Histochemical changes appeared in the decreased activities of cytochrome oxidase, RNA, and Nissl substances after one and two weeks of acrylamide injection and this decrease reached its minimal activity at the end of the experiment for the two doses while acetyl-cholinesterase and DNA were found to be increased. Electron microscopic study revealed irregular outline of nuclear envelop with some nuclear pores, vascular degeneration of cytoplasmic organelles, demyleinated and thinly myleinated axons, and many hypertrophied mitochondria. All these results indicated that acrylamide which is still used in the synthesis of polymers for a variety of industrial applications, is highly neurotoxic