Quercetin in an animal model of spinal cord compression injury: correlation of treatment duration with recovery of motor function

Objectives: We have shown previously that administration of quercetin after spinal cord injury in a rat model induced significant recovery of motor function. In the same model for spinal cord compression injury, we now have correlated the treatment duration with the extent to which motor function is recovered. Methods: Seventy-four male Wistar rats were assigned to eight experimental groups. Mid-thoracic spinal cord injury was produced in the animals of seven groups. Quercetin was administered intraperitoneally in individual doses of 25 mu mol kg(-1). Treatment onset was 1 h after the injury. The length of treatment ranged from one single injection to 10 days, with injection frequencies of two or three times daily. BBB (Basso, Beattie and Bresnahan) scores were obtained and tissue preservation at the site of injury was analyzed. Results: None of the untreated control animals recovered motor function sufficient to walk. When quercetin was administered twice daily over a period of either 3 or 10 days, about 50% of the animals recovered sufficient motor function to walk. Stepping/walking (BBB >= 10) were seen in two of six animals receiving only a single injection and in one of the six animal receiving three injections. Surprisingly, none of the animals that received quercetin injections three times daily recovered the ability to walk (all BBB <= 9). Conclusion: Quercetin administration results in preservation of tissue bridges at the site of injury. Treatment success depends on frequency of administration and overall dose. Spinal Cord (2010) 48, 112-117; doi: 10.1038/sc.2009.111; published online 8 September 2009