The Effect of Eight Weeks of Continuous and Interval Training with Citrus Aurantium Consumption on Autophagy Markers and MyoD Activation in the Muscle Tissue of Elderly Rats

Although exercise training and herbs consumption have protective effects on many diseases, the mechanism of action of exercise training with different intensities and citrus aurantium (CA) extract consumption on the autophagy-dependent MyoD activation pathway is not yet known. The aim of this study was to investigate the effect of eight weeks of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) with CA consumption on the expression of LC3-II, Beclin-1 and MyoD as autophagy related markers in the muscle tissue of elderly rats. 

In this experimental study, 42 elderly female rats were randomly assigned to (1) control (C) (2) MICT, (3) HIIT, (4) MICT + CA, (5) HIIT + CA, (6) CA and (7) sham (normal saline) groups. HIIT was performed at 85-110% VO2max intensity and 15-25 m / min speed and MICT at 65% VO2max intensity and 20-25 m / min speed; 300 mg / kg / day CA was received peritoneally. One-way analysis of variance with Tukey's post hoc test was used to analyze the findings. Findings were analyzed using Graph Pad Prism 8.3.0 software (p ≤ 0.05).

MICT and HIIT increased LC3II, Bclin1 and MyoD gene expression (p ≤ 0.05); The effect of HIIT on MyoD increase was greater than MICT (p ≤ 0.05). CA increased the expression of LC3II and Bclin1 (p ≤ 0.05). MICT + CA and HIIT + CA increased the expression of LC3II, Bclin1 and MyoD in the muscle tissue of elderly rats (p ≤ 0.05). 

It seems that exercise training and CA consumption with different mechanism of action activate autophagy in the soleus muscle tissue, however the simultaneous use of HIIT, MICT and CA also has favorable effects on the autophagy-dependent MyoD activation pathway.