Effect of Endurance Exercise Training on the Kidneys of the Senescence-Accelerated Mouse Prone 8 Model

This study aimed to investigate the impact of endurance exercise training on kidney function in senescence-accelerated mouse prone 8 (SAMP8) mice.

Thirty-week-old male SAMP8 mice were divided into two groups: one group underwent treadmill exercise for 10 weeks (Old-Ex group, n = 12), while the other group remained sedentary (Old-Cont group, n = 12). Additionally, a group of 8- to 10-week-old SAMP8 mice served as a young control (Young-Cont group, n = 22).

Although renal function was similar in the three groups, the renal mRNA expression of monocyte chemoattractant protein-1, macrophage infiltration, and collagen-type III-positive area in the interstitium was significantly higher in the Old-Cont group than in the Young-Cont group. However, these factors were significantly suppressed in the Old-Ex group. Renal protein expression of hypoxia-inducible factor-1α was significantly upregulated in the Old-Cont group compared to the Young-Cont group but was significantly suppressed in the Old-Ex group. In terms of proteins related to mitochondrial function, renal protein expressions of peroxisome proliferator-activated receptor gamma coactivator 1α and medium-chain acyl-CoA dehydrogenase were comparable between the Old-Cont and Young-Cont groups but were significantly upregulated in the Old-Ex group compared to the Old-Cont group. Renal protein expression of cytochrome c oxidase subunit 5B was significantly downregulated in the Old-Cont group compared to the Young-Cont group, and this downregulation was significantly restored by exercise.

This study suggests that endurance exercise training may suppress renal interstitial inflammation and fibrosis in the kidneys of aged SAMP8 mice by preventing renal hypoxia and preserving mitochondrial function.