Diagnostic Imaging Studies on Local and Systemic Erythropoietin Application for Promoting Bone Regeneration in Rat Calvarial Defects

The purpose of this study was to compare the effects of local and systemic application of recombinant human erythropoietin (rhEPO) on the healing of rat calvarial defects. Twenty-four male skeletally-mature Wistar rats were used. Two bone 5 mm critical size defects were created in calvarial bones of each rat. In rats from experimental group I (n = 12), EPO was applied locally on a collagen cone in left defects, whereas a collagen cone soaked with physiological saline was placed in right defects. The rats from experimental group II were injected once intraperitoneally with 4900 IU/kg EPO; a collagen cone was only placed in left defects, whereas the right defects were left empty. The systemic effect of EPO treatment was monitored by haematological analyses on days 0, 30 and 90. Bone healing was monitored via radiography and computed tomography on the same time intervals. The results demonstrated that local EPO application had no significant effect on haemopoiesis, unlike the systemic application. At the same time, it resulted in new bone formation and therefore, could be successfully used as a means of promoting bone regeneration.