Effect of erythropoietin on microvascular anastomosis in rat

Purpose: To investigate the re-endothelialization potential of erythropoietin (EPO) following microvascular anastomosis in rat femoral artery. Methods: Ninety-six male Sprague-Dawley rats weighing between 300 g and 320 g were allocated randomly into two groups (control and EPO, n = 48). Left femoral artery microvascular anastomosis was performed in the rats. The control group was given 0.5 mL of 0.09 % NaCl subcutaneously 48 h postoperatively while the EPO group was given 150 U/kg recombinant human erythropoietin subcutaneously 48 h post-operatively. Tissue was harvested from each group after 1, 3, 5, and 7 days. All of the rats were sacrificed for morphometric analysis. Each arterial segment was analyzed morphometrically using Clemex Image Analysis software by a single examiner. The cross-sectional area of the media and neointima was measured and the intima/media ratio was calculated. Hematocrit measurement was carried out for all the rats. Results: The I/M ratio differed significantly (p < 0.05) between the control and erythropoietin groups, at all time-points. The hematocrit was significantly (p < 0.05) lower in the control group than in the erythropoietin groups on day 7, but not on the other days. Conclusion: This study demonstrates that erythropoietin markedly inhibits neointima formation with accelerated re-endothelialization in rat femoral arteries following microvascular anastomosis.