2.3. Induction of AD

Intracerebroventricular (ICV) injection of STZ, first described by Pelleymounter et al. and modified by Warnock, was used in the current study for the avoidance of cerebral vein penetration [23–25]. Mice were anesthetized with thiopental (5 mg/kg, i.p.), then the mouse's head was stabilized using downward pressure above the ears, and the needle was inserted directly through the skin and skull into the lateral ventricle, which was targeted by visualizing an equilateral triangle between the eyes and the center of the skull to locate the bregma, allowing the needle to be inserted at the following coordinates from the bregma: 1 mm mediolateral, −0.1 mm anteroposterior, and−3 mm dorsoventral. Mice behaved normally approximately 1 min following the injection. The accuracy of the injection technique was established by injecting methylene blue dye that was detected in the lateral ventricles [26].