Blood Biomarker Tenascin-C for Detection of Radiation Cardiotoxicity: An Animal Model

Purpose: The aim of this study was to test the hypothesis that Tenascin-C (TNC) levels increase following thoracic radiotherapy (RT), and that elevated serum TNC levels are associated with corresponding increases in myocardial TNC expression in histopathological specimens, supporting its role as a potential biomarker of radiation-induced cardiotoxicity. Methods: Blood and cardiac tissue samples from rats 8 weeks after thoracic radiotherapy were analyzed to evaluate changes in serum TNC levels and myocardial TNC expression, and their association with radiation exposure. Male Wistar rats were randomized to a single 12-Gy dose of mediastinal irradiation or sham irradiation. Serum TNC levels were assessed with rat ELISA kits. Myocardial TNC expression was assessed using immunohistochemistry, and staining intensity was semi-quantitatively graded by blinded observers. Results: Serum Tenascin-C (TNC) levels were elevated in RT only group compared to control (p < 0.001), paralleled by a marked increase in myocardial TNC expression (p < 0.001). A consistent concordance between circulating and tissue-level TNC was observed, supporting its potential as a biomarker of radiation-induced cardiac injury. Conclusions: Significant associations were observed between radiation exposure and both serum Tenascin-C levels and myocardial Tenascin-C expression, demonstrating a concordance between circulating and tissue findings and supporting Tenascin-C as a promising biomarker of radiation-induced cardiotoxicity.