Modelo de demência de Alzheimer Esporádica induzida por injeção intracerebroventricular de estreptozotocina: Avaliação da memória em camundongos

Abstract

Alzheimer’s disease (AD) is the most common cause of dementia affecting individuals 65 years of age. In Brazil, it is estimated that in 2025 reached 1 million 200 thousand people. AD is characterized by cognitive impairment including memory loss, deposition of senile plaques and intracellular neurofibrillary tangles. Attributed to these changes, in part, to a deficiency in insulin signaling and consequent resistance. The streptozotocin (STZ) is used in the induction of Diabetes Mellitus and its intracerebroventricular (ICV) administration suggests a relationship with AD. This study aimed to standardize the sporadic Alzheimer's disease model induced by intracerebroventricular injection of streptozotocin and evaluate the effect on mice memory. Swiss male mice were divided into two groups; Vehicle, injected with cerebrospinal fluid (CSF), and sporadic dementia, injected with STZ. The animals were anesthetized with xylazine 10 mg / kg ketamine and 90 mg / kg for performing stereotaxic surgery on days 1 and 3 following coordinates: ± 1.5 mm (ML); ± 3.6 mm (DV); ± 0.9 mm (AP). The STZ in a dose of 3 mg / kg per day, totaling 6 mg / kg two days was injected at each point total of 10 L two days and injected into the CSF was also 10μl total of two days. Behavioral tests were performed 15 days after the second administration of STZ, and performed two test schemes, group A and group B. In group A, was assessed working memory and episodic memory through the maze test in Y and the Test object recognition. In group B, was assessed spatial memory through the Morris water maze test. The STZ animals showed no changes in locomotor activity compared to CSF group. The STZ animals showed deficits compared to CSF animals in the Y-maze task, object recognition and water maze. The results demonstrate that streptozotocin compromises the working memory and episodic space, producing a good experimental model for cognitive EAD.