Abstract: Abstract: Objective: To investigate effects of SDF-1α preconditioning on survival and paracrine of H2O2 treated rat marrow mesenchymal stem cells（MSCs）. Methods: MSCs were randomly divided into the control group, H2O2 group, 0.02μg/ml SDF-1α +H2O2 precondition group, 0.2 μg/ml SDF-1α+H2O2　group. LDH were determined after different treatment. MSCs stained with Hoechst33342 for counting apoptosis percentage. Cells proliferation were detected by MTT. ELISA　for detecting VEGF and bFGF. Expressions of VEGF and bFGF in MSCs detected by Western blot. Results SDF-1α preconditioning reduced LDH release and cell apoptosis, and increased cell proliferation. The protein levels of VEGF and bFGF in preconditioning group were significant higher than H2O2 group. Secretion of VEGF and bFGF from preconditioned MSCs were increased when compared with H2O2 group （P＜0.05）. Conclusions: SDF-1α preconditioning reduces cell damage and apoptosis, promotes cell survival and enhances the effects of paracrine.

Key words: SDF-1, precondition, marrow mesenchymal stem cells, paracrine