Erythropoietin Administration Promotes Expression of VEGF in Renal Ischemic–Reperfusion Injury in Rat Model
Supranee Kongkham PhD*, Siriwan Sriwong BSc**, Adis Tasanarong MD***
Affiliation : * Division of Biochemistry, Department of Preclinical Sciences, Faculty of Medicine, Thammasat University (Rangsit Campus), Pathumthani, Thailand ** Laboratory Animal Centre, Thammasat University (Rangsit Campus), Pathumthani, Thailand *** Nephrology Unit, Department of Medicine, Faculty of Medicine, Thammasat University (Rangsit Campus), Pathumthani, Thailand
Background : Acute ischemia-reperfusion (I/R) injury is the most common causes of acute renal failure in daily clinical
practice. It has been recognized that endothelial cell dysfunction and microvascular injury as the pathophysiological changes
during I/R injury. Protective effects of erythropoietin (EPO) have been demonstrated in various experimental models of I/R
induced injury. Therefore, the aim of the present study was to investigate whether EPO administration has renoprotective
effect against acute renal failure I/R injury in rats by promotion of endothelial progenitor cells (EPCs) mobilization and
neovascularization.
Material and Method: Male Sprague-Dawley rats were pretreated with EPO (1,000 IU/kg/day, ip); or the placebo for 3 days
before the induction of I/R procedure. On day 4, the bilateral renal occlusion for 30 min operations to produce renal I/R injury
or treatment with EPO 30 min before the initiation of I/R were done. At the end of the reperfusion period at day 1 day 2 and
day 4, blood and renal tissues were collected to investigate renal function and pathohistological examination. The expression
levels of CAV-1 and CD34 were determined for circulating of EPCs in blood, while CD34, CAV-1 and VEGFR-2 were
investigated for mobilized EPCs in kidney, using real time PCR. The expression level of VEGF was also examined to indicate
the angiogenesis in kidney using real time PCR and western blotting.
Results : In the I/R group, the significantly increased values of serum urea and creatinine were found on Day 1 after ischemia,
as compared to sham group. The development of tubular epithelial cell necrosis, peritubular capillary congestion and mild
interstitial infiltration has been observed in this group. Administration of EPO in I/R rat was significantly improved renal
function and significantly less the tubular damage. The treatment with EPO significantly increased in expression levels of
CD34 and CAV-1 in blood, and also CAV-1, VEGFR-2 and VEGF in kidney tissue in this group, as compared to the I/R group.
Conclusion : These results suggest that treatment with EPO protects the kidney from ischemic acute renal injury via
increasing the mobilization and recruitment of EPCs, resulting in the induction of expression of VEGF that might play an
important role in the repair response.
Keywords : Erythropoietin (EPO), Ischemia/reperfusion injury (I/R injury), Endothelial progenitor cells (EPCs), Angiogenesis
