The investigation of the effect of neural stem cells- conditioned medium on volume changes in different parts of the hippocampus in a model of Alzheimer's disease

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is manifested by learning disability and memory impairment. Well-documented data shows that hippocampal formation as the main and distinctive region in memory establishment is affected by AD. The previous experiments indicated that the neurotrophic factors could increase neurogenesis and promote behavioral performance such as learning g and memory. Therefore, in the current research, we decide to explore the effect of neural stem cells-conditioned medium (NSCs-CM) on the hippocampal volume and its regeneration in a model of AD. Methods: In this study, 30 mice were assigned into three groups: control group, AD+ PBS, and AD + Neural stem cells -Conditioned-Medium (NSCs-CM). For AD model confirmation, a shuttle box test was used following 21 days of Aβ 1-42 injection into lateral ventricles. Then PBS and conditioned- medium for treatment were injected in different groups. One month after the treatment, the mice were anesthetized and perfused. Following histological preparation, serial sections were obtained and stained with cresyl-violate staining. Then, using cavalries’ principal and stereological methods, the total volume of the hippocampus and the absolute volume of its subregions were calculated. Results: The results showed that Aβ induced learning and memory impairment which was indicated by decreasing step-through latency. Also, the Aβ injection significantly decreased the total volume of the hippocampus and absolute volume of the dentate gyrus, CA1, CA2, CA3 relative to the control group. NSCs-CM treatment was able to increase the total volume of the hippocampus and absolute volume of the dentate gyrus, CA1, CA3 relative to the (AD+ PBS group). In the present study, the absolute volume of the CA2 region didn’t significantly increase in the (AD+ NSCs-CM) group in comparison with the (AD+ PBS) group.