Neuroprotective Effects of Aqueous Extract of Achillea Wilhelmsii on Motor Neuron Destruction of Spinal Cord Ventral Horn after Sciatic Nerve Compression in Male Adult Rats

Background & Aims: Peripheral nerve injuries affect both sensory and motor function, resulting in retrograde reaction to neuronal cell bodies in the ventral horn of spinal cord ventral and their destruction. Achillea wilhelmsii is one of the popular medicinal herbs which grow in dry and semitropical areas worldwide. There are several reports indicating the anti-inflammatory, antispasmodic, antibacterial, and antioxidant effects of Achillea. The purpose of this study was to investigate the protective effects of aqueous extract of Achillea wilhelmsii, on alpha neuronal density after sciatic nerve compression in rats. Methods: This experimental study was carried out on 30 male Wistar rats which were divided randomly into 5 groups; group A (control), group B (compression), group C (compression, and treatment with 25 mg/kg aqueous extract), group D (compression and treatment with 50 mg/kg aqueous extract), and group E (compression and treatment with 75 mg/kg aqueous extract). Rats were anesthetized, the thigh muscle of right legs removed, and the sciatic nerve was compressed using a surgical forceps for 60 seconds, and then, thigh muscle and skin were sutured. Intraperitoneal injection of the various doses was performed once every week for 3 weeks. The samples were dissected from lumbar spinal cord by perfusion method and histological slides were prepared serially 28 days after compression. Slides were stained by toluidine blue and erythrosine. Neuronal density of alpha motor neurons of the spinal cord anterior horn was calculated by dissector method. Statistical analysis was performed by Students' t-test and one way ANOVA using SPSS software. Results: The results showed that neuronal density in the compression group decreased significantly compared to the control group (943 ± 59 vs. 1620 ± 51.1, P < 0.001). Neuronal density in group C (1032 ± 40.8), group D (1207 ± 131.3), and group E (1527 ± 46.4) increased significantly in comparison to compression group. The highest neuroprotection was observed in the group which received 75 mg/kg dose of aqueous extract. Conclusion: In conclusion, our results indicate that aqueous extract of Achillea wilhelmsii could protect the sciatic nerve against pathological alterations such as compression.