Background: Peripheral nervous system damages reverse as retrograde to alpha neuron cell bodies and cause spinal degeneration. The fact that herbs, due to their antioxidant properties, have an important role in viability and reproduction of neurons has led to the application of their extracts. Hence, this study was done to determine the neuro-protective effects of the hydroalcoholic extract of Nigella sativa on alpha-motoneurons degeneration after sciatic nerve injury in rats.

Materials and Methods: In this experimental study, 24 male Wistar rats with average bodyweight of 250-300gr were divided into four groups of six: Control, compression, A (compression+hydroalcoholic extract 50 mg/kg), and B (compression+hydroalcoholic extract 75 mg/kg). In compression and treatment groups, the right leg sciatic nerve was subjected to compression (30 seconds). In treatment groups, the extract was injected intraperitoneally two times after compression. After 28 days, lumbar segments of spinal cord, L2-L4, were sampled through perfusion method. After going through tissue passage stages, they were cut in serial sections (7µ) and stained with toluidine blue. Then the density of alpha motoneurons of the spinal cord ventral horn was measured by dissector method.

Results: Neuronal density showed a significant difference between the compression and control groups (p<0.05). Also, in treatment groups A and B, it had a significant increase compared to the compression group (p<0.05).

Conclusion: The results indicated that the hydroalcoholic extract of Nigella sativa has neuro-protective effects and the increase in neuronal density is relevant to the amount of extract used.