Neuroprotective effects of neuroglobin on early stage of brain injury after subarachnoid hemorrhage in rats

Objective To investigate the neuroprotective effects of neuroglobin(NGB) on early stage of brain injury after subarachnoid hemorrhage (SAH) in rats.Methods Sixty clean SD rats were randomly divided into four groups; normal, sham-operation, SAH, and treatment (SAH + intraperitoneal injection of hemin) groups (n = 10 in each group, except in the SAH group, where n = 30).A rat model of SAH was induced by single cisterna magna blood injection.Immunohistochemistry and image analysis techniques were used to observe the NGB immunohistoehemical reaction and the mean optical density value of the temporal cortices at different time points after SAH; the dry and wet methods were used to measure brain water content; in situ apoptosis assay (TUNEL) was used to detect neuronal apoptosis in the temporal lobes.Results ①The mean optical density values in the normal group, and 24 h groups after SAH were 0.133 ±0.021 and 0.236 ±0.028 respectively.② Ngb-positive cells in the temporal cortices increased rapidly after SAH.They reached the peak at 24 h, and then reduced gradually.③ The brain water content in the SAH group was 77.5 ± 0.4% , and it in the treatment group was 76.5 ± 0.6%.The brain water content in the treatment group was less than that in the SAH group, and the difference was statistically significant (P 0.05).④ The degrees of neuronal apoptosis in the temporal lobes were 9.8 ±2.4% and 18.5 ±2.3% in the treatment group and the SAH group.The degrees of cerebral cortical neuronal apoptosis in the treatment group were significantly lower than those in the SAH group (P 0.05). Conclusion NGB-positive cells in rat cerebral cortex after SAH show dynamic changes.NGB given early may decrease cortical neuronal apoptosis of the rat model and reduce the degree of brain edema.It has obvious neuroprotective effects.