Comparison of Effects of High-Fat, High-Protein and Low-Calorie Diets on Klotho Gene Expression and TGF-β Level in Serum and Liver of Old Male Wistar Rats

Background and Objectives: Different diets have important roles in human health and aging. In the current study, we aimed to characterize the Klotho, an anti-aging protein, gene expression and protein level in the serum and assess the protein levels of Transforming growth factor-β and Platelet-derived growth factor in old rats which treated with different diets (high-fat, high-protein, low calorie, high-protein and low calorie).  Materials & Methods: Twenty-five old and five adult rats were treated with high-fat, high-protein, low calorie, high-protein and low-calorie diets for ten weeks. Then, serum protein levels of Klotho, transforming growth factor-β and platelet-derived growth factor and gene expression of Klotho in the liver were assessed using enzyme-linked immunosorbent assay. Results: Protein level of Klotho in the blood serum and expression level of Klotho gene in the liver were increased in high-protein, low-calorie and low-calorie high-protein diets in comparison to control old group (p = 0.000). The levels of transforming growth factor-β and platelet-derived growth factor were increased in low-calorie high-protein group, compared to old group in the liver (p = 0.000). Conclusion: Results revealed that expression of Klotho decreased in old rats while low-calorie high-protein and particularly low-calorie high-protein diets increased this protein. Moreover, these protective diets could enhance transforming growth factor-β and platelet-derived growth factor in liver of rats,veryfieing improvement of the liver function.