Mild hypothermia with subarachnoid transplantation of neural stem cells to repair spinal cord injury in rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Studies have shown that mild hypothermia therapy can regulate the apoptosis, proliferation and differentiation of neural stem cells (NSCs). OBJECTIVE: To explore the effect of mild hypothermia therapy combined with subarachnoid NSCs transplantation on functional recovery from spinal cord injury (SCI) in rats. METHODS: The 20 of 110 Sprague-Dawley rats were randomly selected as sham group, and the remaining 90 rats were used to make spinal cord injury models using modified Allen's method. After modeling, 80 successful models were randomized into SCI, mild hypothermia, NSCs, and combined groups (n=20 per group). Rats in the mild hypothermia group were placed onto an ice blanket at a temperature of (34.0±0.5) ℃ for 3 days. Rats in the NSCs group were raised at 37 ℃ and implanted with 1×104/L NSCs suspension (1 mL, once a day, for continuous 3 days) into the subarachnoid space at 6 hours after modeling. Rats in the combined group were given the combined treatment of mild hypothermia and NSCs transplantation. Motor functional assessment for the bilateral rat lower limbs was performed based on Basso, Beattie and Bresnahan scoring and inclined plate test at 1, 3 days and 1, 2, 3, 4 weeks after modeling. At 4 weeks after modeling, pathological detection by hematoxylin-eosin staining was done; RT-PCR was used to detect expression of Caspase-3, BCL-2 and Syn around the injured region; and electrophysiological recovery of the nerves was assessed based on somatosensory and motor evoked potentials. RESULTS AND CONCLUSION: (1) Lower limb motor function of the rats was improved after NSCs transplantation, mild hypothermia therapy or their combined use, especially in the combined group. (2) At 4 weeks after modeling, there was significant reduced Caspase-3 and significantly increased Bcl-2 and Syn in the combined group compared with the SCI group (both P < 0.05). (3) At 4 weeks after modeling, cystic cavities in the spinal cord formed in the SCI group, became smaller in the NSCs and mild hypothermia groups, and almost disappeared in the combined group. (4) At 4 weeks after modeling, the latency of somatosensory and motor evoked potentials was shortest in the combined group, followed by the NSCs and mild hypothermia groups, and longest in the SCI group. A significant difference was found among groups (P < 0.05). The amplitudes of somatosensory and motor evoked potentials were ranked as follows combined group > NSCs group and mild hypothermia group > SCI group, and there was also a significant difference among groups (P < 0.05). In summary, the combined use of mild hypothermia and NSCs transplantation via the subarachnoid space can promote synaptic regeneration,reduce Caspase-3 mRNA expression, increase Bcl-2 and Syn mRNA expression, and improve motor and electrophysiological functions of the lower limbs in rats.