Expression and cell distribution of neuroglobin in the brain tissue after experimental subarachnoid hemorrhage in rats: a pilot study.

Neuroglobin (Ngb) is a member of the globin superfamily expressed mainly in the nervous system and retina of vertebrates. Accumulated evidence has clearly demonstrated that Ngb has a neuro-protective role enhancing cell viability under hypoxia and other types of oxidative stress. It was suggested that oxidant stress could play an important role in neuronal injury after subarachnoid hemorrhage (SAH). The present study aims to examine the expression of Ngb in the temporal cortex and its cellular localization after SAH. We used a prechiasmatic cistern model of SAH. Ngb expression was examined at 3, 6, 12, 24, 48, and 72 h after SAH by western blot analysis and real-time polymerase chain reaction (PCR). Immunohistochemistry and immunofluorescence were performed to detect the localization of Ngb. Real-time PCR demonstrated that Ngb mRNA levels increased from 3 h after SAH, peaked at 6 h. Western blot showed Ngb protein levels were significantly increased in SAH groups in the temporal cortex and reached the peak at 24 h after SAH. The immunohistochemical staining demonstrated that Ngb was weakly expressed in the cortex in the control group while the enhanced expression of Ngb could be detected in the SAH groups. In addition, immunofluorescence results revealed that the over-expressed Ngb was located in the neuronal and microglia cell cytoplasm. These findings indicated that Ngb might play an important neuro-protective effect after SAH.