Abstract 595: Cardioprotective Effects of Recombinant Human Erythropoietin in Rats with Experimental Autoimmune Myocarditis
Background and Purpose: Erythropoietin (EPO) has been known to have cytoprotective effects on several tissues, presumably through modulation of apoptosis and inflammation. The effect of EPO on myocardial inflammation, however, has not been yet clarified. We investigated the cardioprotective effects of EPO in rats with experimental autoimmune myocarditis (EAM).
Methods and Results: Seven-week-old Lewis rats immunized with cardiac myosin were treated with either EPO (500 IU/day intraperitoneally once a day from day 0 to day 21, n=9) or vehicle (n=8), and were examined on day 22. In EPO treated group, the myocarditis area, which was determined with a color image analyzer, was significantly attenuated compared with in vehicle group (26.6 ± 4.1 % versus 40.5 ± 4.1 %; p < 0.01). Echocardiogram demonstrated significant improvement of left ventricular fractional shortening in EPO treated group than in vehicle group (48 ± 3.2% versus 33.4 ± 2.5%; p < 0.01). These improvements in EPO treated group were along with suppression of mRNAs of tumor necrosis factor- α and interleukin -6 in the hearts (p < 0.05 versus vehicle) by assessing quantitative RT-PCR. EPO also decreased myocyte apoptosis, as assessed by TUNEL staining, significantly (p < 0.05 versus vehicle). Furthermore, immunohistochemical staining for EPO receptor revealed that cardiomyocytes were faintly stained in healthy age-matched rats, while strongly stained in rats with EAM.
Conclusions: EPO, which is widely used in the clinical field, ameliorated the progression of EAM by modulating myocardial inflammation and myocyte apoptosis. The present study may suggest the beneficial effects of EPO for patients with inflammation-related cardiac diseases.