Fahimeh Esfarjani, Ph.D. ,

Background: Physical activity has been found to improve liver health by reducing oxidative stress (OS), possibly through the protein irisin. Heat shock proteins (HSPs) and microRNAs (miRNAs) help regulate the body’s response to stress and maintain cellular health. This study aimed to investigate the expression of the HSP70 gene and protein, miR‑223a, and serum irisin levels in the liver after 8 weeks of endurance exercise or irisin injection. Methods: Twenty‑one mice were randomly assigned to a control group, an endurance training group, and an irisin injection group. The expression of the HSP70 gene and miR‑223a was analyzed using real‑time polymerase chain reaction (PCR), while HSP70 protein levels were measured using immunohistochemistry (IHC) and Western blot analysis. The concentration of irisin in the mouse serum was evaluated using the enzyme‑linked immunosorbent assay (ELISA) method. Results: The endurance training and irisin injection groups exhibited a significant increase in the HSP70 gene (405.30% and 816.03%, respectively) and protein expression (173.89% in IHC, 36.76% in Western blot for endurance training; 206.73% in IHC, 59.80% in Western blot for irisin injection) as well as elevated serum irisin levels (49.75% for endurance training and 60.65% for irisin injection) compared with the control group. In contrast, miR‑223a expression decreased in both the endurance training (21.37%) and irisin injection (52.80%) groups (P < 0.05 in all cases). Mice in the irisin injection group demonstrated higher levels of the HSP70 gene (81.28%) and protein expression (11.99% in IHC and 16.84% in Western blot) and lower miR‑223a levels (39.97%) than those in the endurance training group (P < 0.05). Conclusions: The study concludes that irisin administration can replicate the effects of long‑term endurance exercise on HSP70 and miR‑223a and may have a more significant impact on their production than exercise training alone. © 2024 International Journal of Preventive Medicine.

2023