the neuroprotective effect of alcoholic and aqueous extracts of achillea biebersteinii leaves on spinal motoneurons denegation after sciatic nerve compression in rats

background and aims: neurons are injured under physical, chemical and pathological conditions. the effect of peripheral nervous system injuries may return as retrograde to the cell body of neurons in central nervous system resulting in brain and spinal cord degeneration. because of high content of camphor and borneol, achillea biebersteinii from asteracea family may be effective in prevention the nervous injury progress. so, the aim of the present study was to evaluate the neuroprotective effect of achillea biebersteinii leaves extracts on spinal motoneurons denegation after sciatic nerve compression in rats. methods: this study was carried out on forty eight male wistar rats divided in eight groups including control (a), compression (b), compression and treated with 50 (c), 75 (d), 100 (e) mg/kg of alcoholic extract, compression and treated with 50 (f), 75 (g), 100 (h) mg/kg of aqueous extract of achillea biebersteinii. in compression and experimental groups right sciatic nerve was highly compressed for 60 s. extract was injected intraperitoneally in the first and second week after compression. after four weeks post-operative the lumbar segments of spinal cord were sampled, processed, sectioned and stained with toluidine blue (ph 4.65). using stereological quantitative technique, the number of alpha motoneurons in the right horn of spinal cord were counted and compared with each other. results: according to the results, neuronal density showed significant decrease in compression group compared to control group (p= 0.000). neuronal density in experimental groups c, d and e (50, 75, 100 mg/kg of alcoholic extract) as well as f, g and h (50, 75, 100 mg/kg of aqueous extract) was significantly (p< 0.001) more than that of compression group. data analysis also showed that for both alcoholic and aqueous extract the concentration of 75 mg/kg had stronger activity than concentrations of 50 and 100 mg/kg. conclusion: the results showed that alcoholic and aqueous extracts of achillea biebersteinii leaves have neuroprotective effects on spinal cord alpha motoneurons after injury.