Th17 cells, a recently described subtype of CD4+ eff ector lymphocytes, have been linked to cell-mediated autoimmune and infl ammatory diseases as well as to cardiovascular diseases.However, the participation of IL-17A in myocardial ischemic injury has not been clearly defi ned.We therefore conducted the present study to evaluate IL-17A and Th17-related cytokine levels in a rat model of myocardial infarction (MI).MI was induced in male Sprague Dawley rats by coronary artery ligation.Controls were sham-operated (Sh) or non-operated (C).Blood and samples from the left ventricle (LV) were collected at weeks 1 and 4 post-MI.At week 1, MI animals exhibited increased IL-6, IL-23 and TGF-β mRNA levels with no apparent change in IL-17 mRNA or protein levels in whole LV.Only TGF-β mRNA remained elevated at week 4 post-MI.However, further analysis revealed that IL-17A mRNA and protein levels as well as IL-6 and IL-23 mRNA were indeed increased in the infarcted region, though not in the remote non infarcted region of the LV, except for IL-23 mRNA.The increased expression of IL-17A and Th17-related cytokines in the infarcted region of LV, suggests that this proinfl ammatory pathway might play a role in early stages of post MI cardiac remodelling.