Abstract:

Objective   To study the potential mechanism for treatment of traumatic brain injury with human umbilical cord blood mesenchymal stem cells (HUCBMSCs) in rats. Methods   HUCBMSCs were cultured in vitro and labled with 5-bromo-2-deoxyuridine(Brdu). Sprague-Dawley（SD）rats which suffered from traumatic brain injuries were randomly divided into 3 groups (30 rats in each group): sham-operated group,  control group and treatment group which was injected intravenously with the labled HUCBMSCs. The neurological severity score(NSS) were evaluated in control group and treatment group. Additionally, brain-derived neurotrophic factor (BDNF) was determined at protein level by immunohistochemistry and at mRNA level by in situ hybridization. Results   ①There was no Brdu-labeled cells in sham-operated group and control group. However, Brdu-labeled cells gathered obviously in the damage surrounding area in treatment group and the labeled cells decreased gradually with the time prolonged; ② NSS was obviously improved in treatment group since day 7 after the adminstration of HUCBMSCs; ③There were only a minimal number of nerve cells expressing BDNF in the sham-operated group. Both of control and treatment group showed remarkable increases of BDNF expression which reached a peak at day 14 after injection of HUCBMSCs and then declined gradually. However, BDNF expression increased significantly in treatment group, compared with control group at same time points. Conclusion   HUCBMSCs can survive for at least 4 weeks in brain tissues without application of immunosuppressants in rats. The intravenously injected HUCBMSCs which distribute in the damage surrounding area are more than in other areas. The current study indicates that the brain demage is improved after HUCBMSCs injection and the enhanced BDNF expression benefits in the repair of demaged brain tissues.

Key words: Human umbilical cord blood mesenchymal stem cell； Traumatic brain injury； Brainderived neurotrophic factor；Immunohistochemistry； In situ hybridization