003), B (p=0.003), and C (p=0.004). Similarly, group D presented the lowest axonal density for distal sections of the nerve, which was significantly different from groups A and C (Mann–Whitney test, Bonferroni alpha coefficient: 0.005116;

p=0.003 and p=0.004, respectively). Lapatinib molecular weight Myelinated axons in distal sections (1939, 2160, 1468, 1763 and 2108 axons measured from groups A, B, C, D and E, respectively) had their diameter estimated in each shortest external extension (Fig. 3). Groups A through E presented increasing mean axonal diameters (respectively, 2.17 μm, 2.13 μm, 2.73 μm, 3.07 μm, and 3.59 μm). Group N (1871 myelinated axons counted) had mean axonal diameter of 4.99. Groups A and B presented similar axonal diameters (Mann–Whitney test, adjusted by the Bonferroni coefficient, alpha=0.003414; p=0.567). On the other hand, all other possible comparisons presented

p<0.001. Therefore, we may conclude that, six weeks after surgery, group-E facial nerves presented the largest axonal diameter, followed by that from group D. Schwann cells are glial cells of the peripheral nervous system, surrounding the axon and facilitating the conduction of the nervous impulse. In Wallerian Selleck Selumetinib axonal degeneration, Schwann cells, along with macrophages, mediate the initial steps for myelin removal. Schwann cells proliferate, migrate to form the Büngner bands, and secrete neurotrophic factors that aid axonal guidance and to establish a favorable microenvironment for precise target innervation (Mosahebi et al., 2003). However, there are inherent limitations in their direct use in the experimental nerve repair, as those cells come from restricted sources and have limited availability (Fansa and Keilhoff, 2004 and Wei et al., 2010). Several works

have provided evidence that stem cells may replace Schwann crotamiton cells in that endeavor through in vivo or prior in vitro Schwann cell differentiation ( Dezawa et al., 2001, Cuevas et al., 2002, Evans et al., 2002, Caddick et al., 2006, McKenzie et al., 2006, Chen et al., 2007, Mahay et al., 2008, Ishikawa et al., 2009, Wang et al., 2009, Wakao et al., 2010, Wei et al., 2010, Ladak et al., 2011, Wang et al., 2011 and Salomone et al., 2013). BMSC in the surgical repair of peripheral nerves have improved axonal regeneration and functional recovery ( Dezawa et al., 2001, Cuevas et al., 2002, Chen et al., 2007, Ishikawa et al., 2009, Wang et al., 2009, Wang et al., 2011 and Salomone et al., 2013) that is related to their capability to secrete trophic factors besides Schwann cell The nuclear distribution of p75NTR and Oct-6, as reported for cells in the present study, is consistent with a phenotype for Schwann cells. The in vivo expression of the transcription factor Oct-6 is an important feature favoring axon myelination ( Sim et al., 2002 and Jaegle et al., 2003).