Radiation-induced cognitive dysfunction: the protective effect of ethyol in young rats.

Abstract

To evaluate the protective learning and memory effect of Ethyol in irradiated young rats. One hundred twenty-eight 45-day-old Wistar rats received whole brain fractionated radiation (30 Gy), whereas 48 rats received sham irradiation. Four irradiated subgroups were defined: saline, 37.5 mg/kg, 75 mg/kg, and 150 mg/kg Ethyol. Sequential behavioral studies including one-way and two-way avoidance tasks were undertaken before and after radiation. Before radiation, the performances of all groups were similar. For the one-way avoidance task, at 1, 3, and 6 months postradiation, saline-irradiated rats had a lower percentage of avoidance than sham- or Ethyol- (75 or 150 mg/kg) irradiated rats (p <or= 0.001). Nevertheless, lower percentage of avoidance (p <or= 0.001) was only seen at 1 month postradiation in saline-irradiated rats, after comparison with their preradiation values. For the two-way avoidance task, performed only after radiation, saline-irradiated rats had a lower percentage of avoidance than sham- or Ethyol- (150 or 75 mg/kg) irradiated rats at 1, 2.5, 4.5, and 7.5 months (p = 0.000). Rats treated with Ethyol did not differ from sham-irradiated rats in both avoidance tasks, except for the 37.5 mg/kg-Ethyol group which showed lower performances 6 months postradiation (p = 0.005, one-way avoidance). Treatment with 75 or 150 mg/kg of Ethyol prevents radiation-induced learning and transitory memory dysfunction in young rats.