Background: Hsp-70 production increased following myocardial ischemia. Hsp-70 helps to reduce infarct area through unclear mechanism. It appears that Hsp-70 activates calcineurin and induce antioxidant enzymes such as superoxide dismutase (SOD) and catalase. No work has been done, however, to show correlation between Hsp-70 and calcineurin, SOD and catalase post-acute myocardial infarction. In the present study, therefore, we sought to investigate the relationship of Hsp-70 with calcineurin, SOD and catalase post-acute myocardial infarction (AMI).
Methods: An experimental study involved 24 Wistar rats as models of chronic coronary occlusion. The rats were randomly divided into 4 group: no-intervention after AMI (N), sedentary intervention after AMI (S), exercise intervention after AMI (E), and sham (C). Intervention consisted of 2 weeks of recovery then 4 weeks of sedentary for group S or exercise for group E. Hsp-70, calcineurin, SOD, and catalase expression in heart were evaluated the difference among groups. Correlation between Hsp-70 to other proteins was analysed also.
Results: Hsp-70 and calcineurin was higher in group S and E compared to group N and C. Hsp-70 (MD=0.97, 95% CI 0.60 to 1.34), calcineurin (MD=1.25, 95% CI 0.68 to 1.82, p< 0.05), catalase (MD= 0.57, 95% CI 0.25 to 0.88, p< 0.05), and SOD (0.42, 95% CI 0.14 to 0.69, p< 0.05) significantly higher in Group E compared to S. Sham group had higher SOD and catalase activity than group E. Hsp-70 was correlated with calcineurin (r=0.856, p<0.05). Hsp-70 was correlated with catalase and SOD when the analysis included only groups who had intervention.
Conclusion: Hsp-70 and calcineurin was increased, but catalase and SOD was depleted in post-AMI condition. Exercise improved Hsp-70, calcineurin, catalase, and SOD activities post-AMI. Hsp-70 expression increased directly calcineurin expression.