Effects of secretome obtained from normoxia-preconditioned human mesenchymal stem cells in traumatic brain injury rats

BACKGROUND: The aim of the present study was to investigate whether secretome obtained from normoxia-preconditioned human mesenchymal stem cells causes attenuation of traumatic brain injury (TBI), induced by fluid percussion injury. METHODS: Anaesthetized male Sprague-Dawley rats, immediately after the onset of fluid percussion TBI, were divided into two major groups and given the vehicle solution (1 mL) or secretome (500 mu g) intravenously. Another group of rats was used as sham-operated controls. The functional outcome such as motor (maximum grasp angle) was evaluated by an inclined plane test. Cellular infarction volume was calculated by triphenyltetrazolium chloride staining. Neuronal loss, apoptosis, and neurotrophic factor such as vascular epithelial growth factor (VEGF) expression in the cortex were measured by immunofluorescence staining. All the parameters were assessed on Day 3 after injury. RESULTS: Compared with those of the sham-operated controls, the motor deficits and cerebral infarction of rats after TBI were significantly attenuated by secretome therapy. The TBI-induced neuronal loss and apoptosis were also significantly reduced by secretome therapy. Furthermore, VEGF-positive cells in the ischemic cortex after TBI were further significantly increased by secretome therapy. CONCLUSION: Our results demonstrate that intravenous injection of secretome from normoxia-preconditioned human mesenchymal stem cells may ameliorate TBI-induced rats by reducing neuronal cell loss and apoptosis and promoting VEGF production, resulting in functional outcome improvement. We also recommend that secretome from normoxia-preconditioned human mesenchymal stem cells could be a promising treatment strategy for traumatic brain injury. (J Trauma Acute Care Surg. 2012; 73: 1161-1167. Copyright (c) 2012 by Lippincott Williams & Wilkins)