the effect of crocin and its mechanism of action on chronic pain induced by spinal cord contusion in a rat model

objective: various approaches have been offered for resolution of pain resulting from spinal cord injuries. one approach is the use of herbal and natural products. in the present research, as a preliminary study, we investigate the effect of crocin on chronic pain induced by contusion in the rat spinal cord (sci). methods: we randomly divided female wistar rats into five groups. groups i and ii were contused at the l1 level and immediately treated with crocin (50 mg/kg). these groups were sacrificed after 2 hours and 1 week, respectively. the remaining three groups consisted of group iii (control group), group iv (treated with crocin and no contusion), and group v (the contused group that underwent no treatment). groups iii-v were sacrificed after one week. the mechanical behavioral test that used von frey hairs; the thermal behavioral test that used a hot-plate and the locomotor recovery test with basso, beattie and bresnahn (bbb) scoring were conducted daily to evaluate the extent of injury and recovery of the rats. the calcitonin-gene related peptide (cgrp) was determined in the animals' plasma by the elisa kit. results: the results showed a significant increase in plasma cgrp of contused rats that significantly reduced following crocin treatment. the behavioral tests were not changed significantly due to this treatment. conclusion: the present study shows the beneficial effects of crocin treatment that may occur by decreasing cgrp on chronic pain induced by sci. this project is continuing using higher dose of crocin for longer time.