Variations on nerve regeneration microenvironment and motor function of rat models of spinal cord injury under mild hypothermia / 中国组织工程研究

ABSTRACT

BACKGROUND:Clinical studies have demonstrated that systemic mild hypothermia could significantly reduce the disability and mortality rate of patients with severe traumatic brain injury. In recent years, the researches about the treatment of spinal cord injury by mild hypothermia have been successively carried out. OBJECTIVE:To investigate the effects of mild hypothermia on nerve regeneration microenvironment after spinal cord injury and explore the possible underlying mechanism of nerve regeneration and functional recovery after spinal cord injury in rats. METHODS:Twenty out of sixty-seven rats were randomly selected as the sham group, and other rats were used to establish spinal cord injury models in T9 segment using modified Alen's method. Three rats were excluded for failure in spinal cord injury induction and four rats for death during modeling. The rest 40 rats were randomly and evenly divided into the spinal cord injury and mild hypothermia groups (n=20 rats/group). The rats in the sham and spinal cord injury groups were placed in the operating table with normal temperature, making their rectal temperature at 37.0±0.5℃ for 72 hours. The rats in the mild hypothermia group were placed on ice blanket machine, making their rectal temperature at 34.0±0.5℃ for 72 hours, then the temperature was naturaly rewarmed. RESULTS AND CONCLUSION:Compared with spinal cord injury group, the apoptosis index and the level of aquaporin 4/9 mRNA and protein expression in spinal cord injury tissue were al decreased, somatosensory evoked potential latency and amplitude were recovered, and the motor functional scores were increased in the mild hypothermia group. These results indicate that mild hypothermia play its protective effect on spinal cord injury through attenuating apoptosis of neural cels and decreasing aquaporin 4/9 mRNA and protein expression levels.