ABSTRACT
BACKGROUND: Neural precursor cells exist in the central nervous system (CNS) of adult mammals, characterized fundamentally by such biological properties of multipotential differentiation and capability of maintaining their stable quantity.OBJECTIVE: To investigate the proliferation and migration of the neural precursor cells in adult rat brain following fluid percussion injury (FPI),and explore their role in the repair of CNS damage.DESIGN:Randomized controlled experiment.SETITNG: Laboratory of Pathophysiology, Beijing Institute of Neurosurgery.MATERIALS: This experiment was carried out at the Laboratory of Pathophysiology, Beijing Institute of Neurosurgery. Totally 67 adult Wistar rats were randomized into a control group (n=7) and 5 FPI groups (n=12)sampled 1, 3, 7, 14, and 30 days after FPI, respectively. Each FPI group was further divided into artificial cerebral spinal fluid (CSF) group (n=2),basic fibroblast growth factor (bFGF) group (n=5) and neurotrophin-3 (NT3) group (n=5).METHODS: Lateral fluid percussion brain injury was induced in rats in the FPI group and the rats in the control group were only subjected to craniotomy without percussion. The rats in FPI groups were given intraperitoneal injection of bromodexyuridine (BrdU) at the dosage of 50 mg/kg for three times a day in 1- and 3-day FPI groups, but only once a day in 7-and 14-day groups, with the final dose given 2 hours before sacrifice. The rats in bFGF subgroup and NT-3 subgroup were given bFGF at the total daily dose of 360 ng and NT-3 of 240 ng, respectively, while those in artificial CSF subgroup received perfusion fluid of 4 μL without bFGF or NT3 every day. The dynamic expressions of nestin and BrdU in the rat brain were determined with immunocytochemistry. BrdU labeling method was used to identify the differentiated neural progenitor cells, and nestin expression was used to identify the neural progenitor cells.MAIN OUTCOME MEASURES: Expressions of Brdu, glial fibrillary acidic protein (GFAP)+/Brdu+ and GFAP-/Brdu+ cells in the rat brain of each group at various time points.with the control group, nestin-positive cells in the cortex, hippocampus and subventricular zone on the injured side was obviously increased at 1day after FPI (3.1±1.1 vs 0, 5.5±0.9 vs 1.3±0.8 and 8.1±0.9 vs 2.3±0.8 in each visual field, respectively, P＜0.05), reaching the peak on day 7 (7.5±1.2,10.2±1.5, and 13.6±1.2 in each visual field, respectively) and disappeared BrdU-positive cells in the cortex, hippocampus and subventricular zone on the injured side increased to the highest level 3 days after FPI (12.6±1.5,9.9±1.1, and 13.4±1.0 in each visual field, respectively), but gradually delar zone gradually migrated to the opposite side across the corpus callosum.CONCLUSION: FPI can stimulate the proliferation and migration of neural progenitor cells in adult rat brain, such as in the cortex, hippocampus and subventricular zone, where the nestin-positive cells is the most 7 days after the injury, but BrdU-positive cells is the most 3 days after the injury.