Department of Neurology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, China.
Chin Med J (Engl). 2013 Nov;126(21):4088-92.
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent hematopoietic growth factor that both enhances the survival and drives the differentiation and proliferation of myeloid lineage cells. Recent studies have suggested that GM-CSF has a neuroprotective effect against cerebral ischemia injury, but the molecular mechanisms have been unclear. This study aimed to investigate the influences of a short-acting (half-life 3.5 hours) G-CSF and a long-acting (half-life 40 hours) pegylated G-CSF on the JNK signaling pathway after cerebral ischemia reperfusion.
A total of 52 Sprague-Dawley rats were randomly divided into four groups: a sham group (n = 4), a vehicle with saline (n = 16), a short-acting G-CSF treatment group (n = 16) and a long-acting G-CSF treatment group (n = 16). The cerebral ischemia reperfusion model was established for the sham group and G-CSF treatment groups by middle cerebral artery occlusion (MCAO). Five days post reperfusion, rats were sacrificed and the brains were removed. Changes in neurological function after cerebral ischemia reperfusion was evaluated according to Neurological Severity Score (NSS) and the lesion volume and infarct size were measured by 2,3,5-triphenyltetrazolium chloride staining. The numbers of apoptotic neurons in these ischemic areas: left cerebral cortex, striatum and hippocampus were calculated by TUNEL assay, and expression of JNK/P-JNK, c-jun/P-c-jun in these areas was detected by Western blotting.
Compared with the saline vehicle group ((249.68±23.36) mm(3), (19.27±3.37)%), G-CSF-treated rats revealed a significant reduction in lesion volume (long-acting: (10.89±1.90)%, P < 0.01; short-acting G-CSF: (11.69±1.41)%, P < 0.01) and infarct size (long-acting: (170.53±18.47) mm3, P < 0.01; short-acting G-CSF: (180.74±16.93) mm3, P < 0.01) as well as less neuron functional damage (P < 0.01) and a smaller number of apoptotic neurons in ischemic areas (P < 0.01). The activity of P-JNK and P-c-jun in the cerebral ischemia reperfusion-damaged cortex and hippocampus was significantly decreased in all G-CSF-treated rats (P < 0.05). However, between the long-acting and short-acting G-CSF sets, there were no significant differences found in the activity of P-JNK and P-c-jun in the cortex, hippocampus and striate body (P > 0.05).
Hypodermic injection of 50 µg/kg G-CSF attenuated the damage caused by cerebral ischemia reperfusion in rats, which might be associated with down-regulated activation of the P-JNK and P-c-jun pathway after cerebral ischemia reperfusion. Long-acting G-CSF may be a novel choice for both clinical and basic research in treating cerebral ischemia.
粒细胞-巨噬细胞集落刺激因子（GM-CSF）是一种有效的造血生长因子，既能增强骨髓细胞的存活能力，又能促进其分化和增殖。最近的研究表明，GM-CSF 对脑缺血损伤具有神经保护作用，但分子机制尚不清楚。本研究旨在探讨短效（半衰期 3.5 小时）和长效（半衰期 40 小时）聚乙二醇化 G-CSF 对脑缺血再灌注后 JNK 信号通路的影响。
52 只 Sprague-Dawley 大鼠随机分为四组：假手术组（n = 4）、生理盐水对照组（n = 16）、短效 G-CSF 治疗组（n = 16）和长效 G-CSF 治疗组（n = 16）。通过大脑中动脉闭塞（MCAO）建立假手术组和 G-CSF 治疗组的脑缺血再灌注模型。再灌注后 5 天，处死大鼠并取出大脑。根据神经功能缺损评分（NSS）评估脑缺血再灌注后神经功能的变化，通过 2,3,5-三苯基四氮唑氯化物染色测量脑损伤体积和梗死体积。通过 TUNEL 测定法计算这些缺血区左大脑皮质、纹状体和海马中的凋亡神经元数量，并通过 Western blot 检测这些区域中 JNK/P-JNK、c-jun/P-c-jun 的表达。
与生理盐水对照组相比，G-CSF 治疗组的脑损伤体积（长效：（10.89±1.90）%，P < 0.01；短效 G-CSF：（11.69±1.41）%，P < 0.01）和梗死体积（长效：（170.53±18.47）mm3，P < 0.01；短效 G-CSF：（180.74±16.93）mm3，P < 0.01）明显减小，神经元功能损伤也明显减轻（P < 0.01），缺血区凋亡神经元数量也明显减少（P < 0.01）。所有 G-CSF 治疗组的大脑缺血再灌注损伤皮质和海马中的 P-JNK 和 P-c-jun 活性均明显降低（P < 0.05）。然而，长效和短效 G-CSF 组之间，皮质、海马和纹状体中 P-JNK 和 P-c-jun 的活性无显著差异（P > 0.05）。
皮下注射 50 µg/kg G-CSF 可减轻大鼠脑缺血再灌注损伤，这可能与脑缺血再灌注后 P-JNK 和 P-c-jun 通路的下调激活有关。长效 G-CSF 可能是治疗脑缺血的一种新型选择，既适用于临床研究，也适用于基础研究。
