Rat Model of Alzheimer's Disease

In this study, adult male Wistar rats weighing 250-300 g were purchased from the Pasteur Institute of Iran. They were kept under suitable environmental conditions with a temperature of 22±2°C, 50% humidity, and a 12-h light/dark cycle with free access to water and food. After a one-week adaptation period, the rats were randomly divided into 5 groups of six rats each (control, model, EXP1, EXP2, and EXP3) (Table 1).
For stereotactic surgery, the rats were first weighed and then anesthetized by intraperitoneal injection of ketamine (100 mg/kg) and xylazine (20 mg/kg). The animal was fixed to the device and then a longitudinal incision was made in the posterior part of the skull, according to the Paxinos and Watson Rat Brain Atlas (AP=-4.2, ML=3, DV=3.5) (12 ). A mixture of insulin fibril and trans-chalcone was injected according to Table 1 with a Hamilton syringe. The injection rate was 0.5 μg/min (13 (link)). At the end of the third week after surgery, all groups underwent behavioral tests related to learning and memory.
The experimental protocol was approved by the Animal Ethics Committee of the Science and Research Branch at the Islamic Azad University (Tehran, Iran). The research was performed according to Guidelines of the National Institutes of Health on the principles of laboratory animal care (NIH Publication No. 80-23, revised in 1980).