大鼠脑外伤后伤灶周围皮质脑红蛋白的表达变化

目的观察大鼠脑外伤脑损伤灶周围皮质内脑红蛋白(Ngb)表达的变化,探索其在脑外伤时的神经保护作用。方法采用自由落体硬膜外撞击方法建立脑外伤模型,15只实验动物分为正常对照组及脑损伤12、36h组,应用免疫组织化学和图像分析技术观察伤灶周围第一躯体感觉皮质区(S1)和压部后颗粒细胞b皮质区(RSGb)内Ngb免疫反应阳性信号面积、光密度和累积光密度的变化。结果免疫组化染色显示,Ngb的免疫反应阳性产物于外伤后明显增高,脑损伤36h增高尤为明显。图像分析显示,3组之间阳性信号面积无明显差异(P>0.05);在脑损伤12h组,只有RSGb的光密度较正常对照组明显升高(P<0.05);在脑损伤36h组,两个区域的光密度和累积光密度与正常组比较均明显升高,且与脑损伤12h组比较,除RSGb的累积光密度外均显著升高。结论脑外伤后伤灶周围皮质神经元Ngb表达增高,可能参与了伤后神经元的保护过程。

Expression of neuroglobin in cerebral cortex of traumatic brain injury rats

Objective To observe the expression of neuroglobin (Ngb) in cerebral cortex of traumatic brain injury rats, and investigate the role of neuroglobin in brain injuries. Methods A traumatic brain injury rat model was constructed with Feeney's method. Fifiteen experiment animals were divided randomly into normal control group, 12h-post-trauma group and 36h-post-trauma group (5 each). Immunohistochemistry and image analysis techniques were used to measure the area, optic density (OD) value and integrated optic density (IOD) value of Ngb immunoreactive products in primary somatosensory cortex (S1) and retrosplenial granular b cortex (RSGb), which was located in the inner side and out side of traumatic brain injury cavity in coronal section of rat brain respectively. Results Ngb immunoreactive products were significantly increased after brain trauma, especially in 36h-post-trauma group. The image analysis showed that there was no significant difference of immunoreactive product area in the 3 groups (P<0.05), while only the OD value in RSGb was significantly increased in 12h-post-trauma group compared with that of normal control group (P<0.05). In 36h-post-trauma group, both the OD and IOD values were significantly increased compared with those of normal control group (P<0.05 and P<0.01, respectively), and were also significantly increased compared with those of 12h-post-trauma group (P<0.05 and P<0.01, respectively) excluding IOD in RSGb. Conclusion The expression of neuroglobin in cerebral cortex is increased in traumatic brain injuries, and may play an important role in neuroprotection during brain injures.