Knockdown of TSP-4 alleviates MI/RI-induced myocardial injury and improves brain inflammation by enhancing blood–brain barrier stability

Abstract Myocardial ischemia–reperfusion injury (MI/RI) not only affects cardiac function but also has significant implications for neurological health, potentially leading to cognitive and behavioral impairments. At present, the regulatory role of thrombospondin-4 (TSP-4) in MI/RI has not been reported. A MI/RI mouse model was constructed, and primary cardiomyocytes were isolated. An MI/RI in vitro cell model was constructed using hypoxia/reoxygenation (H/R)-induced H9c2 cells. Haematoxylin and eosin and Masson staining were performed to observe morphological differentiation and fibrosis in myocardial tissues. Evans blue staining was used to analyse blood–brain barrier (BBB) permeability. Behavioural experiments were conducted to assess the learning and cognitive functions of mice. The results showed that the expression of TSP-4 was significantly increased in the blood of patients with ischemic cardiomyopathy and in the myocardial tissue of MI/RI mice. Functional studies showed that TSP knockdown alleviated H/R-induced H9c2 cell injury, including inflammation and oxidative stress. Importantly, interference with TSP-4 alleviated myocardial dysfunction in MI/RI mice. Mechanistically, by improving BBB stability, TSP-4 knockdown alleviated neuronal injury and the inflammatory response in mice induced by MI/RI. Further research found that silencing TSP-4 alleviated cognitive impairment and improved learning in MI/RI mice. Knockdown of TSP-4 improved MI/RI-induced functional cardiomyocyte injury. In addition, by enhancing BBB stability, TSP-4 silencing alleviated MI/RI-induced neurological injury and cognitive impairment in mice.