The attenuating effect of erythropoietin (EPO) on the expression of myeloperoxidase (MPO) in bleomycin-induced pulmonary fibrosis in rats

Purpose:The enzyme MPO is well known to participate in the fibrotic pathway with inflammatory and apoptotic actions.EPO is a multiple functional cytokine with anti-inflammatory and anti-apoptotic properties.Aim of this study was to investigate the role of EPO on the expression of MPO in bleomycin (BLM)-induced pulmonary fibrosis (PF) in rats. Methods:Fifty Wistar rats (300gr) were divided into five groups of 10 animals each: 1)control animals, 2)intratracheal (i.t) and intraperitoneal (i.p) injection of saline (0.5ml/kg), 3)BLM hydrochloride (7.5mg/kg) i.t injection, 4)BLM hydrochloride (7.5mg/kg) i.t injection followed by EPO i.p injection (2000 iu/kg), 5)saline (0.5ml/kg) i.t injection followed by EPO i.p injection (2000 iu/kg).All rats were sacrified after 14 days.The expression of MPO was immunohistochemically measured and a scale of 4 grades (A:0-25%, B:25-50%, C:50-75%, D:75-100%) was used to evaluate it. Results:In groups 1,2 and 5 (control groups), MPO was expressed in the low grades A (80%) and B (20%).In group 3, MPO was expressed in the high grades C (20%) and D (80%).Finally, in group 4, MPO was expressed only in the low grades A (70%) and B (30%).The expression of the enzyme took place in the high grades for group 3 (BLM group) and in the lower grades for group 4 (BLM+EPO group) (p Conclusions:Administration of EPO after the BLM i.t injection (group 4) resulted in significant lower expression of MPO in comparison with the BLM group (group 3).More studies are required to clarify the mechanisms of the protective action of EPO on PF.Maybe it is a new potential target for the therapeutic treatment of PF.