Abstract:Background: Cardiac contusion is an important cause of mortality after blunt chest trauma (BCT). The aim of this study was to investigate the therapeutic effi cacy of the usage of aminoguanidine (AG), in myocardial damage occurring after BCT, alone and in combination with methylprednisolone (MP). Methods: Thirty-fi ve female Wistar albino rats were randomly assigned to fi ve groups (n = 7) including: sham controls (S); only cardiac contusion (CONT); cardiac contusion treated with methylprednisolone (CONT+MP); cardiac contusion treated with aminoguanidine (CONT+AG); and cardiac contusion treated with methylprednisolone and aminoguanidine (CONT+MP+AG). Seven days following the treatments, heart and serum specimens were evaluated histopathologically, immunohistochemically, and biochemically in all groups. Results: Serum AOPP and Tn-I levels increased signifi cantly after cardiac contusions. Haemorrhage, tissue degeneration, and necrosis development was evident following contusions. Increased iNOS expression in myocardial tissue was signifi cantly decreased in the CONT+AG+MP group compared to CONT+AG and CONT+MP groups (p = 0.001 and p = 0.011, respectively). The combined treatment of AG and MP increased Bcl-2 expression signifi cantly after contusions compared to the other treatment groups. Conclusions: Combined usage of AG, a selective iNOS inhibitor, with MP, in cardiac contusions, showed a more powerful cardioprotective effect by increasing Bcl-2 expression and reducing iNOS expression (Tab. 3, Fig. 4, Ref. 33). Text in PDF www.elis.sk.