Protective effect of aerobic physical activity on mir-21 and mir-146-b changes in renal tissue of male rats exposed to cadmium chloride

Cadmium (Cd) is a nephrotoxic environmental pollutant, and microRNAs have been recently investigated as potential biomarkers for the diagnosis and pathology study of certain diseases. The present study aimed to determine the protective effect of aerobic physical activity on the changes of mir-21 and mir-146-b in renal tissue caused by cadmium chloride in male rats.

This experimental study was conducted on 32 healthy adult male Wistar rats with a mean weight of 250±30 grams and an age of 12 weeks. They were randomly assigned to four groups (n=8):   1- control group (C), 2- Exercise group (E), 3- Cadmium chloride group (CC), and 4- Cadmium+exercise group (CE). Aerobic exercises were performed five times a week for five weeks. It was run at a speed of 27 meters per minute with a zero slope for 16 min. During the study period, the rats received the cadmium chloride as gavage (a daily dose of three milligrams per kilogram of body weight diluted with distilled water orally). The mir-21 and mir-146-b were measured by the reverse transcription polymerase chain reaction (RT-PCR) method. The data were analyzed in SPSS software (version 24) using a one-way analysis of variance and Bonferroni's post hoc test at a significance level of 0.05.

The present study demonstrated a significant lower expression of miR-21 (P=0.001) and a higher expression of miR-146-b (P=0.014) in the cadmium group than in the control group. Compared to the control group, aerobic training illustrated a more balanced state through a significant increase in miR-21 gene expression, as well as a significant decrease in miR-146-b.

The obtained results indicated that regular moderate-intensity exercise in cadmium-treated rats leads to microRNA secretion regulation associated with renal toxicity.