EXOGENOUS HEAT-SHOCK COGNATE PROTEIN HSC7O PREVENTS AXOTOMY-INDUCED DEATH OF SPINAL SENSORY NEURONS

Elevation of intracellular heat shock protein (Hsp)70 increases resist ance of cells to many physical and metabolic insults. We tested the hy pothesis that treatment with Hsc70 can also produce that effect, using the model of axotomy-induced neuronal death in the neonatal mouse. Th e sciatic nerve was sectioned and in some animals purified bovine brai n Hsc70 was applied to the proximal end of the nerve immediately there after and again 3 days later. Seven days postaxotomy, the surviving se nsory neurons of the lumbar dorsal root ganglion (DRG) and motoneurons of the lumbar ventral spinal cord were counted to assess cell death. Axotomy induced the death of approximately 33% of DRG neurons and 50% of motoneurons, when examined 7 days postinjury. Application of exogen ous Hsc70 prevented axotomy-induced death of virtually all sensory neu rons, but did not significantly alter motoneuron death. Thus, Hsc70 ma y prove to be useful in the repair of peripheral sensory nerve damage.