There is provided in the present application a peptide comprising the amino acid sequence of YEKLLDTEI (SEQ ID NO : 1) or a functional variant thereof. The peptide is an active peptide for the treatment of a central nervous system injury. The present application also provides a chimeric peptide comprising an active peptide and an internalization peptide. The present application also provides a pharmaceutical composition comprising the active peptide or the chimeric peptide, as well as medical use of the active peptide or the chimeric peptide.