Optimization strategies for reversible myocardial injury caused by ultrasonic cavitation effects using an orthogonal experimental design

The aim of this study is to investigate the effect of the optimal parameter combination of ultrasonic cavitation on reversible myocardial injury in rat heart using an orthogonal experimental design. An orthogonal experimental design was used to inject microbubbles via the tail vein at a certain microbubble concentration and input speed, and to irradiate the long-axis section of the rat left ventricle according to different levels of mechanical index (MI), duty cycle (DU), and irradiation time (IT), respectively. Myocardial injury was assessed by serum levels of lactate dehydrogenase (LDH). Cardiac function was measured by echocardiography and two-dimensional spot tracking. Myocardial blood perfusion was evaluated using peak signal intensity (PI). The expression levels of apoptosis related proteins were detected by Western blot. ELISA was used to detect the levels of inflammatory factors and oxidative stress factors. Histopathological changes of heart, liver, lungs, spleen and kidney were observed with hematoxylin and eosin (HE) stain. The results of orthogonal experiment showed that the order of ultrasonic parameters influencing LDH release into blood was DU, IT and MI. Serum LDH levels and myocardium PI were significantly increased post-cavitation. Cardiac function in rats decreased slightly at 3 days after cavitation treatment, and largely recovered by day 14. Myocardial oxidative levels were slightly elevated, anti-apoptosis ability was weakened, and no significant changes in inflammatory factors were observed. By 14 day, myocardial oxidative levels and anti-apoptotic ability returned to baseline. HE staining revealed that cardiomyocytes exhibited different degrees of edema following ultrasonic cavitation, endocardial damage severity significantly exceeding epicardial damage, this damage resolved by day 14. The orthogonal experimental design effectively optimized ultrasonic cavitation parameter, improving myocardial cell membrane permeability, increasing myocardial blood perfusion, and inducing reversible short-term cardiac dysfunction in rats, providing laboratory data support ultrasonic cavitation for cardiovascular diseases therapy.