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Previous animal studies have shown that stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor-4 (CXCR4) signaling pathway plays an important role in the targeted migration of bone marrow-derived mesenchymal stem cells (BMSCs) to the injured area.In the present study,we aimed to investigate the potential role of chemotactic SDF-1/CXCR4 signaling pathway in the homing of transplanted BMSCs to the injured cochlea after noise-induced hearing loss (NIHL) in a rat model.White noise exposure (110 dB) paradigm was used for hearing loss induction in male rats for 6 hours in 5 days.Distortion-product otoacoustic emission (DPOAE) responses were recorded before the experiment and post noise exposure.Hoechst 33342-labeled BMSCs and CXCR4 antagonist (AMD3100)-treated BMSCs were injected into the rat cochlea through the round window.SDF-1 protein expression in the cochlear tissue was assayed using west blot assay.The number of labeled BMSCs reaching the endolymph was determined after 24 hours.SDF-1 was significantly increased in the cochlear tissue of rats in the noise exposure group than in the control group.The number of Hoechst 33342-labeled BMSCs reaching the endolymph of the cochlea was significantly smaller in the AMD3100-treated BMSCs group than in the normal BMSCs group.Our present findings suggest that the SDF-1/CXCR4 signaling pathway has a critical role in BMSCs migration to the injured cochlea in a rat model of noise-induced hearing loss.