Beneficial effects of local profound hypothermia and the possible mechanism after experimental spinal cord injury in rats.

Objective: The primary focus of this study was to investigate the effects of local profound hypothermia and to explore the possible mechanism in adult rats with spinal cord injury.
Study Design and Methods: Spinal cord injury models were established by placing aneurysm clips on T10. An epidural perfusion device was applied to maintain a steady temperature (18 °C) for 120 min with gradual rewarming to 37 °C Total hypothermic duration lasted up to about 170 min. The expression of axon regeneration inhibitors was tested by Western blot and real-time PCR. Luxol Fast Blue (LFB) stain and Bielschowsky silver stain were used to observe spinal cord morphology. Motor function of the hind limbs (BBB score) was monitored for 21 days.
Results: The expressions of RhoA, ROCK-II, NG2, Neurocan, Brevican, and Nogo-A were downregulated by regional hypothermia (RH) after spinal cord injury. Subsequent observation showed that rats that had received RH had an alleviated demyelinating condition and a greater number of nerve fibers. Furthermore, the RH group achieved higher BBB scores than the spinal cord injury (SCI) group.
Conclusions: Recovery of hind limb function in rats can be promoted by local profound hypothermia; this may be caused by the suppression of axon regeneration inhibitors.