Role of Preoperative Stress in Myocardial Injury during Noncardiac Surgery in Wistar Rats

Four groups of old Wistar rats were used: anesthesia only (An), noncardiac surgery (NS), stress exposure for 5 days followed by NS (SNS), and an intact control. Increases in proinflammatory cytokines and C-reactive protein were not observed within 10 days after surgery, suggesting no inflammation. Stress was evident from the highest corticosterone level in the SNS rats. Myocardial injury after NS (MINS) occurred in the SNS rats as judged from structural and metabolic disorders and an increase in the blood concentration of High-sensitive cardiac troponin I (hs-cTnI). Although ischemic and hypoxic zones in the myocardium were detected in the An and NS rats, the rats did not develop MINS, displaying neither oxidant-antioxidant imbalance nor, most importantly, an increase in hs-cTnI. The study showed for the first time that "simple" aseptic noncardiac surgery in combination with preoperative stress can induce MINS in healthy old Wistar rats. A decrease in superoxide dismutase was proposed as an additional biomarker of MINS.