Frontiers in Cellular Neuroscience Cellular Neuroscience

Abstract

In addition, FGF-2 exerts neurotrophic and neurite outgrowth activities in culture (Moftah, 2007). However, several studies suggest that the regeneration processes of the spinal cord occurring after body transection and tail amputation are different (Chernoff et al., 2003). During body spinal cord regeneration, a decreasing rostrocaudal gradient in FGF-2 mRNA expression along the brain stem-spinal cord axis was observed by Moftah et al. (2008) in intact Pleurodeles. We demonstrated a long-lasting up-regulation of FGF-2 mRNA expression in response to spinal transection at the mid trunk level, both in brainstem and in the spinal cord below injury. Moreover, we showed that FGF-2 was up-regulated in neuroglial, presumably undifferentiated, cells. Astrocytes, also a source of FGF-2, become reactive following both central and peripheral nervous system injury (Colburn et al., 1999; Clarke et al., 2001). These activated astrocytes undergo hyper-trophy and show up-regulated expression of GFAP (Eng, 1985; Web, 2008), which is thus used as a key indicator of astrocyte activation (Reilly et al., 1997). Furthermore, following a physical insult to brain or spinal cord, reactive astrocytes in the vicinity of the damage site show increased FGF-2 immunoreactivity (Gomez-Pinilla et al., 1992; Clarke et al., 2001; Smith et al., 2001). However, it has also been suggested that following injury the observed increase in FGF-2 would induce astrocyte proliferation and contribute to astrologists, which has a negative effect on regeneration (Gomez