Effects of Reg-2 on survival of spinal cord neurons in vitro

Regeneration gene protein 2 (Reg-2) is a small secreted protein expressed in motor and sensory neurons of spinal cord during developmental stages and following injury of peripheral nerves. Reg-2 appears to act as a neurotrophic factor and protects injured neurons from death during regeneration. To illustrate these potential protective effects in vitro, we investigated the blocking effects of Reg-2 antibodies on the survival of primary cultured spinal cord neurons and astrocytes, as well as on neurite outgrowth. In addition, the effects of Reg-2 in neuron injury models induced by peroxide and mitochondrial poisoning were assessed. Our results showed that Reg-2 antibody markedly reduced survival and neurite outgrowth from neurons, whereas astrocyte survival was unaffected. Addition of Reg-2 into the culture medium had no effect on neuron survival or neurite outgrowth. However, the addition of the Reg-2 into culture media after peroxide treatment or cellular hypoxia insult induced by mitochondrial poisoning can reduce lactate dehydrogenase release levels and cell death. Thus, the data suggests that Reg-2 is essential for the survival and neurite outgrowth of developing spinal cord neurons but not the survival of glial cells, and that Reg-2 plays protective effects on spinal cord neurons against injury in vitro.