OBJECTIVEBasic fibral growth factor (bFGF) might have a role in the restoration and regeneration of injured neurons following hypoxic-ischemic brain damage (HIBD), but its mechanism has not been fully elucidated. Nestin is an intermediate filament protein expressed in dividing cells during the early stages of CNS development, but it can be reinduced in adults during regeneration of injured neurons after CNS injury. This study investigated the effect of exogenous bFGF on nestin expression in neonatal rats following hypoxia-ischemia (HI) and to explore the possible mechanism.

METHODSEighty-four 7-day-old SD rats were randomly assigned into a Sham-operation group, a HIBD group and a bFGF intervention group (n=28 each). HIBD was induced by ligation of the left carotid artery along with 8% oxygen exposure in neonatal rats from the latter two groups. The Sham-operation group was not subjected to HI. The bFGF intervention group received an intraperitoneal injection of bFGF daily (4000 U/kg). Each group was randomly subdivided into groups sacrificed immediately, at 3, 12 and 24 hrs and 3, 7 and 14 days after HI (n=4). The expression of nestin in the cerebral cortex, hippocampus and extraventricular zone was examined with immunohistochemical staining and image quantitative analysis.

RESULTSNestin was weakly expressed in the hippocampus and extraventricular zone and not expressed in the cortex in the Sham-operation group. The nestin in the cortex, hippocampus and extraventricular zone was significantly increased after HIBD, peaking at 7 days. bFGF treatment increased the nestin expression in the cortex, hippocampus and extraventricular zone and statistical differences were observed from 1 to 14 days after HI when compared with the untreated HIBD group.

CONCLUSIONSExogenous bFGF can up-regulate the nestin expression in neonatal rats following HIBD. The effects of restoration and regeneration of bFGF on injured neurons may be associated with increased nestin expression in neonatal rats.