The effect of preconditioning with high-intensity training on tissue levels of G-CSF, its receptor and C-kit after an acute myocardial infarction in male rats

Abstract

Background: Exercise training is known as a practical way to increase cardioprotection against stress, and it seems that stem cell recruitment is one of its mechanisms. The purpose of the present study was to investigate the effect of preconditioning with High-intensity interval training (HIIT) on tissue levels of G-CSF, its receptor and C-Kit following acute myocardial infarction in male rats.

Methods: Twenty Male Wistar rats were randomly divided into 4 groups of control, MI, HIIT, and HIIT+MI. Training groups performed 2 weeks of high intensity interval training in 4 sections. The first section consisted training in 3 days and 2 sessions in each day (4 × 2 min with 35-40 m/min and 3 × 2 min with 25-30 m/min between high intervals. The second part included 2 days of training (4 × 2 min with 40 to 45 m/min and 3 × 2 min with 28 to 32 m /min). The third part was performed in 3 days with one more repetition. The fourth section consisted 2 days of training and with one more repetition compared to section 3. For induction of myocardial infarction, subcutaneous injection of isoprenaline was used. CK, total CK, LDH, and troponin T were measured in serum and G-CSF, G-CSFR and C-Kit proteins were measured by the Western Blot method in the heart tissue.

Results: The results of this study showed that enzymes of CK, total CK, LDH, troponin T had a significant increase in both MI and HIIT+MI groups compared to the other two groups (P < 0.001) and these indices in the MI group were significantly higher than the HIIT+MI group. Also, the results demonstrated that G-CSF, G-CSFR and C-Kit protein expression in the heart tissue significantly increased after MI. As well as, 2 weeks of HIIT training significantly increased G-CSF and C-kit in the training group compared to the control group, but the training caused that these proteins does not increase in HIIT+MI group as much as MI group.

Conclusions: Along with other protective pathways, high intensity interval training can increase cardioprotection and decrease heart injuries through the increase in G-CSF, G-CSFR and C-kit level.

Keywords: Acute myocardial infarction; Cardioprotection; High-intensity interval training; Preconditioning.

Fig. 1

The steps of the graded and exhaustion exercise test in order to evaluate of endurance capacity

Fig. 2

Cell injury markers in experimental groups. Results were presented as means ± SD. a: Blood levels of creatine kinase total (CK_total ), b: blood levels of lactate dehydrogenase (LDH), c: Blood levels of troponin T (cTI), d: Blood levels of creatine kinase (CK.). * p < 0.001 compared to the control; # p < 0.05 compared to the HIIT, and @ p < 0.001 compared to the HIIT+MI

Fig. 3

The amount of fibrosis in the heart tissue in (a) control group, b HIIT group, c MI group, and (d) HIIT+MI group. The green color represents the amount of tissue fibrosis (× 40 magnification)

Fig. 4

Necrosis in the heart tissue in (a) control, b HIIT, c MI, and d HIIT+MI groups. Neutrophil accumulation, edema and separation of fibers (Arrows show) (× 40 magnification)

Fig. 5

Protein expression in experimental groups (a, b, c, d). a: * p < 0.001 and # p < 0.05 compared to the control group; + p < 0.05 compared to the HIIT+MI. b: * p < 0.001 compared to the control and HIIT groups; # p < 0.01 compared to the control group; + p < 0.05 compared to the HIIT group. c: * p < 0.001 compared to 3 other groups; # p < 0.001compared to 3 other groups. d: Western blot images and comparison of the protein bands of G-CSF, G-CSFR, C-kit with β-actin (as a loading control) between groups. The ratio of these proteins to β-actin expression in experimental groups was shown and described in a, b, c sections