Time-related effects of general functional training in spinal cord-injured rats

OBJECTIVES: This prospective, randomized, experimental study with rats aimed to investigate the influence of general treatment strategies on the motor recovery of Wistar rats with moderate contusive spinal cord injury. METHODS: A total of 51 Wistar rats were randomized into five groups: control, maze, ramp, runway, and sham (laminectomy only). The rats underwent spinal cord injury at the T9-T10 levels using the NYU-Impactor. Each group was trained for 12 minutes twice a week for two weeks before and five weeks after the spinal cord injury, except for the control group. Functional motor recovery was assessed with the Basso, Beattie, and Bresnahan Scale on the first postoperative day and then once a week for five weeks. The animals were euthanized, and the spinal cords were collected for histological analysis. RESULTS: Ramp and maze groups showed an earlier and greater functional improvement effect than the control and runway groups. However, over time, unexpectedly, all of the groups showed similar effects as the control group, with spontaneous recovery. There were no histological differences in the injured area between the trained and control groups. CONCLUSION: Short-term benefits can be associated with a specific training regime; however, the same training was ineffective at maintaining superior long-term recovery. These results might support new considerations before hospital discharge of patients with spinal cord injuries.

Cannabidiol-treated Rats Exhibited Higher Motor Score After Cryogenic Spinal Cord Injury

Cannabidiol (CBD), a non-psychoactive constituent of cannabis, has been reported to induce neuroprotective effects in several experimental models of brain injury. We aimed at investigating whether this drug could also improve locomotor recovery of rats submitted to spinal cord cryoinjury. Rats were distributed into five experimental groups. Animals were submitted to laminectomy in vertebral segment T10 followed or not by application of liquid nitrogen for 5 s into the spinal cord at the same level to cause cryoinjury. The animals received injections of vehicle or CBD (20 mg/kg) immediately before, 3 h after and daily for 6 days after surgery. The Basso, Beattie, and Bresnahan motor evaluation test was used to assess motor function post-lesion one day before surgery and on the first, third, and seventh postoperative days. The extent of injury was evaluated by hematoxylin-eosin histology and FosB expression. Cryogenic lesion of the spinal cord resulted in a significant motor deficit. Cannabidiol-treated rats exhibited a higher Basso, Beattie, and Bresnahan locomotor score at the end of the first week after spinal cord injury: lesion + vehicle, day 1: zero, day 7: four, and lesion + Cannabidiol 20 mg/kg, day 1: zero, day 7: seven. Moreover, at this moment there was a significant reduction in the extent of tissue injury and FosB expression in the ventral horn of the spinal cord. The present study confirmed that application of liquid nitrogen to the spinal cord induces reproducible and quantifiable spinal cord injury associated with locomotor function impairments. Cannabidiol improved locomotor functional recovery and reduced injury extent, suggesting that it could be useful in the treatment of spinal cord lesions.

Evaluation of the effects of hyperbaric oxygen therapy for spinal cord lesion in correlation with the moment of intervention

Study design: Experimental, controlled, animal study. Objectives: To evaluate the functional effect of hyperbaric oxygen therapy administered shortly, one day after, and no intervention (control) in standardized experimental spinal cord lesions in Wistar rats. Setting: Sao Paulo, Brazil. Methods: In all, 30 Wistar rats with spinal cord lesions were divided into three groups: one group was submitted to hyperbaric oxygen therapy beginning half an hour after the lesion and with a total of 10 one-hour sessions, one session per day, at 2 atm; the second received the same treatment, but beginning on the day after the lesion; and the third received no treatment (control). The Basso, Beattie and Bresnahan scales were used for functional evaluation on the second day after the lesion and then weekly, until being killed 1 month later. Results: There were no significant differences between the groups in the functional analysis on the second day after the lesion. There was no functional difference comparing Groups 1 and 2 (treated shortly after or one day after) in any evaluation moment. On the 7th day, as well as on the 21st and 28th postoperative days, the evaluation showed that Groups 1 and 2 performed significantly better than the control group (receiving no therapy). Conclusion: Hyperbaric chamber therapy is beneficial in the functional recovery of spinal cord lesions in rats, if it is first administered just after spinal cord injury or within 24 h. Spinal Cord (2012) 50, 502-506; doi: 10.1038/sc.2012.16; published online 6 March 2012