Comparative Study of the Distribution and Localization of Neuroglobin Expression in the Mammalian Brain: A Literature Review

Neuroglobin (Ngb) was recently identified as a member of the vertebrate hemoglobin family. Several studies have been conducted on Ngb in mammals, but none have compared its expression and localization among different mammals. This review compared the distribution and localization of Ngb expression and explained the different functions of Ngb in the brains of mammals. Intel’s integrated performance primitive (IPP) analysis was employed to obtain the expression levels in each region of the mammalian brain. Ngb is widely expressed in the adult yak brain and distributed in different areas, similar to its expression in cattle. The relative expression of the Ngb gene in the cerebral cortex (262.69 ± 9.19) was significantly higher than that in the cerebellar cortex (137.00 ± 7.29), hippocampus (1.00 ± 0.22), medulla oblongata (3.43 ± 0.76), striatum (7.65 ± 0.61) and olfactory bulb (2.14 ± 1.22). Findings in the rat brain showed low Ngb protein expression. The mouse brain showed Ngb over expression in a transgenic variant (Ngb-Tg), while in the human brain, the level of Ngb was higher in the hypothalamus, amygdala and pontine tegmental nuclei than in other parts of the brain. The expression levels, distribution and localization of Ngb differ across the brains of different mammals, so it is appropriate to explore the precise distribution and localization of Ngb before comparison or analysis in these mammals.