Objective: To investigate the permeability of beta-NGF through blood-brain-barrier (BBB) in neonatal and adult rats, and the spatial distribution of beta-NGF in different brain regions in hypoxic-ischemic (HI) and normal neonatal rats.
Methods: To investigate the overall permeability of beta-NGF through BBB, beta-NGF labeled with I-125 was injected into adult rats, neonatal rats and HI neonatal rats via tail vein. The radioactivity of brain tissue and blood was examined and analyzed 30 min after injection. Also, brain regions including the basal forebrain, frontal cortex, hippocampus, hypothalamus, cerebellum, bulbus olfactorius and hypophysis, of all the rats were dissected and radioactivity was examined to investigate the spatial specificity of NGF permeation through BBB.
Results: Statistically significant results were observed in I-125-beta-NGF contents in brain tissues of adult rats group, neonatal rats group and HI neonatal rats group (P < 0.05). Compared to the HI neonatal rats" brain with the highest I-125-beta-NGF contents, normal neonatal rats ranks the second while the adult rats were the lowest. While for the spatial specificity examination part, I-125-beta-NGF in both HI group and control group were widely distributed in basal forebrain, frontal cortex, hippocampus, cerebellum and bulbus olfactorius. But the radioactivity in frontal cortex, hippocampus and cerebellum of HI groups are statistically higher than control groups (P < 0.05).
Conclusion: beta-NGF can more easily penetrate the BBB of newborn rats than adult rats via peripheral venous administration and this effect can be enhanced by HI insult. Also, this HI-induced permeation of beta-NGF through BBB is more obvious in frontal cortex, hippocampus and cerebellum.
[1]Jilin Univ, Hosp 1, Dept Neonatol, 71 Xinmin St, Changchun 130021, Jilin, Peoples R China.
[2]Jilin Univ, Hosp 1, Dept Colorectal & Anal Surg, Changchun 130021, Jilin, Peoples R China.
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