Previous studies have shown that, in the process of SCI and other CNS disorders, BMP4 is reported to be mainly expressed by most neural cell types (Xiao et al., 2010), astrocytes (Wang et al., 2011) and oligodendrocyte progenitor cells (Sabo et al., 2009; Zhao et al., 2005; Li et al., 2008). Here, BMP4 is linked to central nervous system disorder.