A previous study showed that, 1 week after avulsion of the spinal nerve root, small motor neurons (< 500 μm2) negative for 27 kDa heat shock protein (HSP27) immunoreactivity died and only large (> 500 μm2) HSP27-positive motor neurons survived in the spinal cord ventral horn. This was followed by the enhancement of HSP27 expression in motor neurons observed after mild crush of the spinal nerve root.
Dr. Lin Li and co-workers from Nanjing Medical University in China investigated whether preconditioning crush can increase the survival rate of motor neurons, which is the first to demonstrate that loss of ventral motor neurons after nerve root avulsion is partially prevented by preconditioning crush. This injury tolerance might act through the induction of HSP27 by preconditioning crush, which inhibits the upregulation of neuronal nitric oxide synthase to attenuate the cytotoxic effects of nitric oxide following crush. The relevant article has been published in the Neural Regeneration Research (Vol. 9, No. 5, 2014).