Protective effect of the antioxidative peptide SS31 on ionizing radiation-induced hematopoietic system damage in mice.

Ionizing radiation (IR) causes severe damage to the hematopoietic system; thus, it is necessary to explore agents or compounds that can reduce this damage. SS31 is a mitochondria-targeted peptide that can scavenge cellular reactive oxygen species (ROS) and inhibit the production of mitochondrial ROS. Therefore, in this study, we discuss the protective effect of SS31 on IR-induced hematopoietic system damage. Our results showed that treatment with 6 mg/kg SS31 elevated the survival rate of lethally irradiated mice and increased the numbers of white blood cells, red blood cells, hemoglobin and platelets in mice exposed to 4 Gy whole-body irradiation. In addition, SS31 administration improved the number of hematopoietic stem/progenitor cells (HSPCs) and the self-renewal and reconstitution abilities of these cells in irradiated mice. The elevation of ROS levels is the main cause of IR-induced hematopoietic system damage, and SS31 can effectively reduce the ROS level in HSPCs. The above results suggest that SS31 can protect the hematopoietic system from radiation-induced damage by reducing cellular ROS levels.