▁injury ; ▁the ▁ax ons ▁and ▁my elin ▁deg ener ate , ▁but ▁the ▁end one ur ium ▁remains . ▁In ▁the ▁later ▁stages ▁of ▁reg ener ation ▁the ▁remaining ▁end one ur ial ▁t ube ▁direct s ▁ax on ▁growth ▁back ▁to ▁the ▁correct ▁targets . ▁During ▁W aller ian ▁deg ener ation , ▁Schw ann ▁cells ▁grow ▁in ▁ordered ▁columns ▁along ▁the ▁end one ur ial ▁t ube , ▁creating ▁a ▁band ▁of ▁Bü ng ner ▁cells ▁that ▁protect s ▁and ▁pres erves ▁the ▁end one ur ial ▁channel . ▁Also , ▁macro ph ages ▁and ▁Schw ann ▁cells ▁release ▁ne uro t roph ic ▁factors ▁that ▁enh ance ▁re - g row th . ▁ ▁Central ▁nerv ous ▁system ▁reg ener ation ▁ ▁Un like ▁peri pher al ▁nerv ous ▁system ▁injury , ▁injury ▁to ▁the ▁central ▁nerv ous ▁system ▁is ▁not ▁followed ▁by ▁extensive ▁reg ener ation . ▁It ▁is ▁limited ▁by ▁the ▁in hib itory ▁influ ences ▁of ▁the ▁gli al ▁and ▁ext rac ell ular ▁environment . ▁The ▁host ile , ▁non - per miss ive ▁growth ▁environment ▁is , ▁in ▁part , ▁created ▁by ▁the ▁migration ▁of ▁my elin - associ ated ▁in hib itors , ▁ast ro cy tes , ▁o lig od end ro cy tes , ▁o lig od end ro cy te ▁prec urs ors , ▁and ▁micro gl ia . ▁The ▁environment ▁within ▁the ▁C NS , ▁especially ▁following ▁tra uma , ▁counter act s ▁the ▁repair ▁of ▁my elin ▁and