HIF-1α/SDF-1/CXCR4 axis reduces neuronal apoptosis via enhancing the bone marrow-derived mesenchymal stromal cell migration in rats with traumatic brain injury

Mesenchymal stromal injection is a promising therapy for traumatic brain injury (TBI). The aim of this study was to explore the effects of the HIF-1 alpha/SDF-1/CXCR4 axis on neuron repair in TBI rats through improving the bone marrow-derived mesenchymalstromal cells (BMSCs) migration. TBI rat models were established. The rats were treated with exogenous SDF-1, and then the neuronal apoptosis in TBI rats was measured. BMSCs from rats were collected, and the roles of NF-kappa B p65 expression in nuclei, overexpression of SDF-1 and HIF-1 alpha, as well as downregulation of CXCR4 in BMSC migration were identified. HIF-1 alpha- and SDF-1- treated BMSCs were transplanted into TBI rats, after which the neuronal apoptosis and activity of the HIF-1 alpha/SDF-1/CXCR4 axis were detected. Consequently, we found SDF-1 elevated the HIF-1 alpha/SDF-1/CXCR4 activity and presented protective roles in TBI rat hippocampal neurons with reduced neuronal apoptosis. SDF-1 promoted BMSC migration in vitro, and co-effects of SDF-1 and HIF-1 alpha showed strong promotion, while CXCR4 inhibition suppressed BMSC migration. BMSC transplantation activated the HIF-1 alpha/SDF-1/CXCR4 axis and reduced neuronal apoptosis in TBI rats. To conclude, our study demonstrated that the HIF-1 alpha/SDF-1/CXCR4 axis could enhance BMSC migration and alleviate neuronal damage and apoptosis in TBI rats. This study provided novel options for TBI therapy.