Abstract:

Objective  To investigate effects of recombinant human erythropoietin (rhEPO) on chronic cervical spinal cord compression in rats. Methods  80 Wistar rats were randomly separated into 4 groups. Control rats (group A) received sham operations (n=5) and were executed by laminectomy. Experimental rats were subjected to compression injury in the C5 segment of the spinal cord by posterior progressive compression and subsequently subdivided into 3 groups. Group B (n=25) was treated with 1mL saline by IV. Groups C (n=25) and D (n=25) were treated with 500u/(kg·d) and 5000u/(kg·d) rhEPO by IV respectively. Limb motor function was scored using BBB standards 3, 7, 14, 21 and 28d after injury. The distribution and quantities of EPO and EPO-R in the compressed segment of the spinal cord were determined by immunobiochemical assay. Finally, apoptosis in the spinal cord was evaluated using TUNEL staining and flow cytometry at indicated time points. Results  The data indicated that expression of EPO-R increased significantly with aggravative level of chronic cervical spinal cord compression, as groups C and D exhibited higher BBB scores at all observed time points compared with group B(P＜0.01). Using TUNEL staining and FCM, we observed that rhEPO could profoundly inhibit motor neuron apoptosis in the spinal cord (P＜0.01) on day 21. Additionally, rhEPO treatment demonstrated a strong dose-dependent effect. Conclusions  rhEPO administration decreases motor neuron apoptosis in the spinal cord and improves spinal cord and motor functions following chronic cervical spinal cord compression. Moreover, continuing treatment with low doses of rhEPO shows a positive therapeutic effect.

Key words: Cervical spinal cord； Chronic spinal cord compression； recombinant human Erythropoietin (rhEPO)； Apoptosis； Rats， Wistar