Abstract

Background: In the current study, our specific aim was to characterize the Klotho protein and expression levels in the hippocampus and prefrontal cortex of old rats treated with different diets (high-fat, high-protein, low-calorie, high-protein and low-calorie). Methods: Rats were treated with high-fat, high-protein, low-calorie, low-calorie high-protein diets for 10 weeks and then behavioral and molecular assessments were evaluated. Results: Statistical analysis showed the percentage of open arm time was increased in the high-protein, low-calorie and low-calorie high-protein groups compared with old control (old-C) rats. The percentage of open arm entries was increased in the low-calorie and low-calorie high-protein group compared with old-C rats. The body weight and serum triglyceride were decreased in the low-calorie and low-calorie high-protein groups in comparison to control old rats. Low-calorie and low-calorie high-protein treatments statistically enhanced caspase-3 level compared with old-C rats in the hippocampus and prefrontal cortex. Treatment of old rats with high-protein, low-calorie and low-calorie high-protein could increase Klotho-alpha level compared with control old rats. The levels of Klotho-alpha, c-fos and brain-derived neurotrophic factors were decreased in the low-calorie high-protein group in Klotho inhibitor's presence compared with the low-calorie high-protein group. Conclusion: According to our findings, Klotho-alpha level was reduced in old rats. Low-calorie, high-protein and particularly low-calorie high-protein diets increased this protein level and consequently increased neuronal plasticity and improved memory function.