Effects of recombinant human erythropoietin on mandibular distraction osteogenesis

To evaluate the effects of subcutaneous administration of recombinant human erythropoietin (rHuEPO) on regeneration formation and quality during mandibular distraction osteogenesis.

Sixteen adult male New Zealand rabbits were used in this study. Ethical approval was obtained from the Animal Research Institute of Selcuk University, Konya, Turkey. Subjects were randomly divided into 2 groups. Distraction osteogenesis (DO) was performed with a custom-made distractor on the left mandibles of rabbits. In the experimental group, 4 doses of 150 IU/kg rHuEPO were administered at 48-hour intervals. The first dose was given immediately after surgery. Control subjects received 0.5 mL/kg isotonic solution in the same manner. After 2 days of latency, mandibles were distracted 1 mm/day at 12-hour intervals for 5 days. A 5-mm lengthening was achieved. All animals were sacrificed after 30 days of consolidation. Afterward, samples were prepared for histomorphometric evaluation of newly formed bone area.

The number of osteoblasts and blood vessels was significantly higher, whereas the number of osteoclasts was significantly lower, in the experimental group than in the control group (P < .05). In the experimental group, the area of new bone formation was greater than in the control group (P < .05). Moreover, fibroblast and collagen numbers per unit area were higher in the experimental group. However, this finding was not statistically significant (P > .05).

The subcutaneous administration of rHuEPO improves the rate and quality of bone-healing during distraction osteogenesis. However, the short-term favorable effects of rHuEPO in this study should be extended with long-term investigations before clinical application.