The Expression Of Neuroglobin And Chemokine Gene Under Hypoxic-ischemic Brain Damage

The globins are proteins famed for their oxygen-caning capacity. Two types are known in vertebrates:hemoglobin and myoglobin.Recently neurogobin(NGB) has been identified, mainly in the brain, which is a monomer with a high oxygen affinity. The globin has a distinct function similar to myoglobin. To investigte its function to greater degree, we studied the normal distribution of NGB gene in brain at first. Using nucleic acid in situ hybridization (ISH) and immunohistochemistry method ,we found that NOB mRNA and NGB protein were abundant in the brain of normal adult rat. A large number of NGB mRNA and NGB- immunoreactive(NGB-IR) positive cells were distributed in the neurons of the rat brain. They were both distributed in the plasm of neurons. Notably, the number of NOB mRNA and NGB-IR positive cells in cerebral cortex was much more than in hippocampus and cerebellum, especially in piriform cortex. Second, the dynamic change of expression of NOB mRNA in cerebral tissue was studied by using adult rat ischemic brain damage model and RT-PCR technique. We discovered that the expression of NOB gene showed time-depended pattern. It increased rapidly at 1 minute after ischemia, kept high level at 5 minute, then returned to normal at 15 minute. It then increased again, but more slowly. At last, we studied the expression of NOB mRNA in 13 different tissue of human. The result showed that there was high expression in fetal kidney and normal adult liver besides brain. In conclusion, our results showed for the first time that:(1) NOB gene was expressed extensively in normal rat brain and distributed in neurons,suggesting a critical role of NOB gene for the activity of neurons.(2) The expression of NOB mRNA in cerebral 4 tissue increased rapidly after ischemia,suggesting that NOB may have important function in the adaptative protection process of hypoxic-ischemic brain damage (HIBD).(3) The expression of NGB mRNA was found in other tissues besides brain, suggesting that NGB gene is not specific in nervous system.