Use of Erythropoietin as adjuvant therapy in nerve reconstruction

Background and aims: Adjuvant therapies may improve the outcome after nerve reconstruction. We analyzed the influence of recombinant human Erythropoietin (rHuEpo), which has proven angiogenic and neuroprotective effects, on the quality of peripheral nerve regeneration. Methods: Thirty two female Lewis rats underwent nerve reconstruction by means of tubulization (groups I and II) or autologous sciatic nerve grafting (groups III and IV). Groups I and III received daily subcutaneous rHuEpo injections over 2 weeks (1,000 U/kg bw) with normal saline injections as controls (groups II and IV). Data on histology and muscle weight were collected after 7 weeks. Axon count and diameter were assessed by a new method based on digital segmentation. Results: Atrophy of the tibial muscle was less severe in the rHuEpo-treated group compared to controls resulting in significant higher muscle weight quotients (p=0.006). The same trend was found in the gastrocnemius muscle, but without being statistically significant. No significant differences in axon count or axon diameter were detected in the presence of rHuEpo treatments. Conclusion: Our findings give evidence for a positive effect of Erythropoietin on functional recovery after nerve grafting. Muscle recovery benefited from rHuEpo administration despite absence of improved neural morphology. Semi-automated axon detection facilitated accurate morphometrical assessment.