For histological analysis mice were injected a pentobarbital overdose and perfused with PBS/paraformaldehyde as previously described (Camarero et al., 2001; Sanchez-Calderon et al., 2010), before tissue extraction (cochlea and femur; Rodriguez-de la Rosa et al., 2014). Decalcified samples were dehydrated and embedded in paraffin (Panreac Química), as previously described (Aburto et al., 2012). Cochlear and bone marrow cytoarchitecture was evaluated using representative paraffin sections (7 μm thick) and Nissl or hematoxylin-eosin staining (Reagan et al., 2011).