Department of Pathology, Kinki University School of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
Neurotox Res. 2009 Nov;16(4):378-89. doi: 10.1007/s12640-009-9081-6. Epub 2009 Jul 10.
Edaravone is a novel free radical scavenger that is clinically employed in patients with acute cerebral infarction, but has not previously been used to treat traumatic brain injury (TBI). In this study, we investigated the effect of edaravone administration on rat TBI. In particular, we used immunohistochemistry to monitor neural stem cell (NSC) proliferation around the area damaged by TBI. Two separate groups of rats were administered saline or edaravone (3 mg/kg) after TBI and then killed chronologically. We also used ex vivo techniques to isolate NSCs from the damaged region and observed nestin-positive cells at 1, 3, and 7 days following TBI in both saline- and edaravone-treated groups. At 3 days following TBI in both groups, there were many large cells that morphologically resembled astrocytes. At 1 and 7 days following TBI in the saline group, there were a few small nestin-positive cells. However, in the edaravone group, there were many large nestin-positive cells at 7 days following TBI. At 3 and 7 days following TBI, the number of nestin-positive cells in the edaravone group increased significantly compared with the saline group. There were many single-stranded DNA-, 8-hydroxy-2'-deoxyguanosine-, and 4-hydroxy-2-nonenal-positive cells in the saline group following TBI, but only a few such cells in the edaravone group following TBI. Furthermore, almost all ssDNA-positive cells in the saline group co-localized with Hu, nestin, and glial fibrillary acidic protein (GFAP) staining, but not in the edaravone group. In the ex vivo study, spheres could only be isolated from injured brain tissue in the saline group at 3 days following TBI. However, in the edaravone group, spheres could be isolated from injured brain tissue at both 3 and 7 days following TBI. The number of spheres isolated from injured brain tissue in the edaravone group showed a significant increase compared with the saline group. The spheres isolated from both saline and edaravone groups were immunopositive for nestin, but not Tuj1 or vimentin. Moreover, the spheres differentiated into Tuj1-, GFAP-, and O4-positive cells after 4 days in culture without bFGF. This result indicated that the spheres were neurospheres composed of NSCs that could differentiate into neurons and glia. Edaravone administration inhibited production of free radicals known to induce neuronal degeneration and cell death after brain injury, and protected nestin-positive cells, including NSCs, with the potential to differentiate into neurons and glia around the area damaged by TBI.
依达拉奉是一种新型的自由基清除剂，临床上用于治疗急性脑梗死患者，但尚未用于治疗创伤性脑损伤 (TBI)。在这项研究中，我们研究了依达拉奉给药对大鼠 TBI 的影响。具体而言，我们使用免疫组织化学监测 TBI 损伤区域周围神经干细胞 (NSC) 的增殖。两组大鼠在 TBI 后分别给予生理盐水或依达拉奉 (3mg/kg)，然后按时间顺序处死。我们还使用体外技术从损伤区域分离 NSCs，并在 TBI 后 1、3 和 7 天观察两组中巢蛋白阳性细胞。在两组大鼠 TBI 后 3 天，有许多形态上类似于星形胶质细胞的大型细胞。在 TBI 后 1 和 7 天的生理盐水组中，有少量小的巢蛋白阳性细胞。然而，在依达拉奉组中，TBI 后 7 天有许多大的巢蛋白阳性细胞。TBI 后 3 和 7 天，依达拉奉组巢蛋白阳性细胞数量明显多于生理盐水组。TBI 后，生理盐水组有许多单链 DNA、8-羟基-2'-脱氧鸟苷和 4-羟基-2-壬烯醛阳性细胞，但依达拉奉组只有少数此类细胞。此外，生理盐水组中几乎所有的 ssDNA 阳性细胞均与 Hu、巢蛋白和神经胶质纤维酸性蛋白 (GFAP) 染色共定位，但依达拉奉组中没有。在体外研究中，仅在 TBI 后 3 天的生理盐水组的损伤脑组织中才能分离出球体。然而，在依达拉奉组中，TBI 后 3 天和 7 天均可从损伤脑组织中分离出球体。依达拉奉组从损伤脑组织中分离出的球体数量与生理盐水组相比显著增加。从生理盐水和依达拉奉组分离的球体均对巢蛋白呈免疫阳性，但对 Tuj1 或波形蛋白呈免疫阴性。此外，在没有 bFGF 的情况下，在培养 4 天后，这些球体分化为 Tuj1、GFAP 和 O4 阳性细胞。这一结果表明，这些球体是由 NSCs 组成的神经球，可分化为神经元和胶质细胞。依达拉奉给药抑制了已知在脑损伤后诱导神经元变性和细胞死亡的自由基的产生，并保护了巢蛋白阳性细胞，包括具有分化为神经元和胶质细胞的潜能的 NSCs，这些细胞位于 TBI 损伤区域周围。
