Changes in Aβ42, Neprilysin, and γ-Secretase in the Hippocampus of Male Rats Alzheimer’s model: The Effects of Aerobic Training and Omega-3 Intake

Abstract

Background: Alzheimer›s disease (AD) is characterized by excessive deposition of the amyloid-β peptide (Aβ) in the central nervous system and reducing its level is the goal of many medications. This study aimed to investigate the effect of aerobic training and omega-3 intake on Aβ42, neprilysin, and γ-secretase levels in the hippocampus of male rats Alzheimer›s model. Methods: Fifty male Wistar rats (age: 12 weeks-old and weight: 222.31±11.91 g), were divided into the five groups including control Alzheimer’s (AC), Alzheimer’s with omega-3 intake (AO), Alzheimer’s training (AT), Alzheimer’s with omega-3 intake and training (AOT) and Healthy Control (HC). AD was induced by the injection of homocysteine (60mM) into the rat brain ventricle. Training on the treadmill with a speed of 20 m/min (60 minutes and 5 days/week) was applied. The supplement group received omega-3 supplement 800 mg/kg of body weight, daily for eight weeks. Levels of Aβ42, γ-secretase, and neprilysin protein were measured using ELISA method. In data analysis, one-way ANOVA and Tukey test as post hoc were used (P<0.05). Results: The obtained results showed that the level of Aβ42 in the hippocampus of AC group was significantly higher than that of the HC group (P=0.001). Also, the level of Aβ42 in the hippocampus of AC group was significantly higher as compared to AO, AT, and AOT groups (P values 0.001, 0.007, and 0.003 respectively). The γ-Secretase level in the hippocampus of AC group was significantly higher than that in the HC group (P=0.001). Moreover, the γ-secretase levels in the hippocampus of the AC group were significantly higher compared to AO, AT, and AOT groups (P values: 0.002, 0.001, and 0.001 respectively). There was no significant difference in neprilysin levels of the hippocampus among the research groups (P=0.534). Conclusion: It appears that exercise training and omega-3 consumption, can affect amyloidogenic pathways through reducing the level of γ-secretase, and lead to reduced level of hippocampus Aβ in AD subjects. Therefore, aerobic exercise training and omega-3 intake can be studied as a complementary therapy in Alzheimer’s patients.