Influence of Stress Resistance on Myocardial Expression of the Pro-Autophagic Protein Beclin-1 After Cardiac Contusion in Experimental Setting

Abstract

Objective. Evaluation of myocardial expression of the pro-autophagic protein Beclin-1 after cardiac contusion in experimental animals with different stress resistance.Materials and methods. The study included 68 white mongrel male rats weighing 250–300 g. After ranking for extreme variants of stress resistance, moderately stress-resistant rats (N=36) were excluded from the study. The remaining animals were split into the control (N=16) and study (N=16) groups, each group composed of 8 high stress resistant and 8 low stress resistant rats. In the study group, 24 hours after inflicted cardiac contusion, 5×5 mm myocardial tissue specimens were sampled from the intraventricular septum, anterior walls of the left and right ventricles, histological sections were made, and a reaction with primary polyclonal Anti-Beclin-1 antibodies was performed. Beclin-1 expression was evaluated under the microscope.Results. Immunohistochemical evaluation revealed a statistically significant increase in Beclin-1 protein expression (P=0.0002) in the cytoplasm of cardiomyocytes in the study group vs the control group, regardless of animals’ baseline stress resistance. However, expression of Beclin-1 protein in the myocardium of highly stress-resistant rats (Me=4.3; LQ=4.0; HQ=4.3) was significantly higher versus low-resistant animals (Me=3.6; LQ=3.3; HQ=3.6) (P=0.0009).Conclusion. Increased expression of Beclin-1 protein in the post-traumatic period of experimental cardiac contusion indicates autophagic flux activation. Intensity of autophagy varied depending on the animal’s stress resistance.

Keywords

• cardiac contusion
• autophagy
• beclin-1
• stress resistance