Neudesin, a secreted factor, promotes neural cell proliferation and neuronal differentiation in mouse neural precursor cells

Neudesin encodes a secreted signal with neurotrophic activity in neurons. Most neurotrophic factors are involved in neural cell proliferation and/or differentiation. However, the role of neudesin in neural development remains to be elucidated. We examined the expression of neudesin in mouse embryonic cerebral cortex and cultured mouse neural precursor cells and its roles in neural development. Neudesin was expressed in the embryonic cerebral cortex early in development. Its expression was observed mainly in the preplate, where mostly postmitotic neural cells existed. Because neudesin mRNA was expressed in the neural precursor cells before the appearance of neurons, the roles of neudesin in neural development were examined by using the precursor cells. Neudesin significantly promoted neuronal differentiation and overrode the undifferentiated state of the neural precursor cells sustained by fibroblast growth factor 2 (FGF2). In contrast, it inhibited the differentiation of astrocytes. In addition, neudesin transiently promoted neural cell proliferation early in the developmental process. The effect on cell proliferation was distinct from that of FGF2, a self-renewal-promoting factor for neural precursor cells. The differentiation was mediated though activation of the protein kinase A (PKA) and phosphatidylinositol-3 kinase (PI-3K) pathways. In contrast, the proliferation was mediated through the mitogen-activated protein kinase and PKA pathways. The expression profile and activity indicate that neudesin plays unique roles in neural development. The present findings have revealed new potential roles of neudesin in neural cell proliferation and neuronal differentiation.     

Subventricular zone neural precursor cell responses after traumatic brain injury and binge alcohol in male rats

Traumatic brain injury (TBI) is a major cause of disability worldwide. Additionally, many TBI patients are intoxicated with alcohol at the time of injury, but the impact of acute intoxication on recovery from brain injury is not well understood. We have previously found that binge alcohol prior to TBI impairs spontaneous functional sensorimotor recovery. However, whether alcohol administration in this setting affects reactive neurogenesis after TBI is not known. This study, therefore, sought to determine the short- and long-term effects of pre-TBI binge alcohol on neural precursor cell responses in the subventricular zone (SVZ) following brain injury in male rats. We found that TBI alone significantly increased proliferation in the SVZ as early as 24 hr after injury. Surprisingly, binge alcohol alone also significantly increased proliferation in the SVZ after 24 hr. However, a combined binge alcohol and TBI regimen resulted in decreased TBI-induced proliferation in the SVZ at 24 hr and 1 week post-TBI. Furthermore, at 6 weeks after TBI, binge alcohol administered at the time of TBI significantly decreased the TBI-induced neuroblast response in the SVZ and the rostral migratory stream (RMS). The results from this study suggest that pre-TBI binge alcohol negatively impacts reparative processes in the brain by decreasing short-term neural precursor cell proliferative responses as well as long-term neuroblasts in the SVZ and RMS.     

小鼠脑组织发育期细胞增生与分化的改变(英文)

目的探讨小鼠脑组织发育期间的细胞增生与分化。方法C57/BL6小鼠分别于出生后10天(P10)、17天(P17)、24天(P24)不同脑发育期,每天注射新生细胞标记物 5- 溴脱氧尿嘧啶核苷(BrdU),连续注射7天,并分别于末次注射后四周将小鼠处死、取脑。采用免疫组化染色及免疫荧光染色分别检测细胞增生(BrdU)与细胞分化(NeuN、APC、Iba1和S100 β)。结果细胞增生随着脑组织发育快速下降,并以皮层和纹状体区细胞增生最显著。皮层在发育早期以及纹状体和海马CA区在发育各期检测到极少数为新生神经元细胞,多数分化为胶质细胞;海马齿状回以神经元细胞再生为主;胶质细胞的再生随脑组织发育的成熟而逐渐减少。结论研究证实小鼠脑组织细胞的增生、分化以及存活与发育时期、脑组织区域相关。     

小鼠脑组织发育期细胞增生与分化的改变

目的探讨小鼠脑组织发育期间的细胞增生与分化。方法C57／BL6小鼠分别于出生后10天（P10）、17天（P17）、24天（P24）不同脑发育期,每天注射新生细胞标记物5一溴脱氧尿嘧啶核苷（BrdU）,连续注射7天,并分别于末次注射后四周将小鼠处死、取脑。采用免疫组化染色及免疫荧光染色分别检测细胞增生（BrdU）与细胞分化（NeuN、APC、Iba1和S100β）。结果细胞增生随着脑组织发育快速下降,并以皮层和纹状体区细胞增生最显著。皮层在发育早期以及纹状体和海马CA区在发育各期检测到极少数为新生神经元细胞,多数分化为胶质细胞;海马齿状回以神经元细胞再生为主;胶质细胞的再生随脑组织发育的成熟而逐渐减少。结论研究证实小鼠脑组织细胞的增生、分化以及存活与发育时期、脑组织区域相关。     

Hyperbaric oxygen treatment promotes neural stem cell proliferation in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage

Hyperbaric oxygen therapy for the treatment of neonatal hypoxic-ischemic brain damage has been used clinically for many years, but its effectiveness remains controversial. In addition, the mechanism of this potential neuroprotective effect remains unclear. This study aimed to investigate the influence of hyperbaric oxygen on the proliferation of neural stem cells in the subventricular zone of neonatal Sprague-Dawley rats (7 days old) subjected to hypoxic-ischemic brain damage. Six hours after modeling, rats were treated with hyperbaric oxygen once daily for 7 days. Immunohistochemistry revealed that the number of 5-bromo-2′-deoxyuridine positive and nestin positive cells in the subventricular zone of neonatal rats increased at day 3 after hypoxic-ischemic brain damage and peaked at day 5. After hyperbaric oxygen treatment, the number of 5-bromo-2′- deoxyuridine positive and nestin positive cells began to increase at day 1, and was significantly higher than that in normal rats and model rats until day 21. Hematoxylin-eosin staining showed that hyperbaric oxygen treatment could attenuate pathological changes to brain tissue in neonatal rats, and reduce the number of degenerating and necrotic nerve cells. Our experimental findings indicate that hyperbaric oxygen treatment enhances the proliferation of neural stem cells in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage, and has therapeutic potential for promoting neurological recovery following brain injury.     

Long‐term antiepileptic drug administration during early life inhibits hippocampal neurogenesis in the developing brain

Certain antiepileptic drugs (AEDs) that are commonly used to treat seizures in children also affect cognition, and these effects can persist into adulthood, long after drug withdrawal. Widespread enhancement of apoptosis may be one mechanism underlying these lasting cognitive changes. Whether AEDs affect other processes in brain development during early postnatal life has not, however, been systematically analyzed. Here we determined whether chronic administration of common AEDs during early life alters cell proliferation and neurogenesis in the hippocampus. Postnatal day 7 (P7) rats received phenobarbital, clonazepam, carbamazepine, valproate, topiramate, or vehicle for 28 days. Bromodeoxyuridine was administered on P34 to label dividing cells. Cell proliferation was assessed 24 hr later, and cell survival and differentiation were assessed 28 days later. Phenobarbital and clonazepam significantly inhibited cell proliferation by 63% and 59%, respectively, and doublecortin immunoreactivity (indicator of neurogenesis) in the dorsal hippocampus was also significantly decreased by 26% and 24%, respectively. Survival of new cells steadily decreased in phenobarbital and clonazepam groups over 28 days. Reduced cell proliferation and survival resulted in fewer new neurons in the dentate gyrus, as confirmed by neuronal counting on P62. There were, however, no differences in cell distribution pattern or differentiation toward neuron and glial cells when phenobarbital and clonazepam groups were compared with controls. There were no changes in rats exposed to carbamazepine, valproate, or topiramate. Thus, inhibiting cell proliferation, survival, and neurogenesis in the developing hippocampus may be another potential mechanism underlying brain impairment associated with certain AED therapies in early life. © 2009 Wiley‐Liss, Inc.     

Upregulation of RAGE at the blood‐brain barrier in streptozotocin‐induced diabetic mice

Deposition of amyloid‐β peptide (Aβ) in the brain of diabetes is poorly understood. The receptor for advanced glycation end products (RAGE) at the blood‐brain barrier (BBB) is critical for regulation of Aβ homeostasis in the brain. In this studies, we used streptozotocin‐induced diabetic mice to observe the expression of RAGE at the BBB by Western blot and immunocytochemical analysis, and the in vivo blood‐to‐brain influx transport of ¹²⁵I‐Aβ_1–40 using the permeability surface area product (PS) and brain capillary uptake. In the diabetic mice with hyperglycemia (>16.0 mmol/L) at 6 weeks, RAGE expression at the BBB was significantly upregulated, no significant changes of RAGE levels were found at 1 and 3 weeks after diabetes induction. The data of PS and brain capillary uptake for Aβ showed significant RAGE‐dependent transport of Aβ across the BBB and substantial RAGE‐dependent brain capillary uptake at 6 weeks after diabetes induction. We conclude that the upregulation of RAGE at the BBB contributes to cerebral Aβ deposition in the diabetes. Synapse 63:636–642, 2009. © 2009 Wiley‐Liss, Inc.     

Phenytoin enhances the phosphorylation of epidermal growth factor receptor and fibroblast growth factor receptor in the subventricular zone and promotes the proliferation of neural precursor cells and oligodendrocyte differentiation

Phenytoin is a widely used antiepileptic drug that induces cell proliferation in several tissues, such as heart, bone, skin, oral mucosa and neural precursors. Some of these effects are mediated via fibroblast growth factor receptor (FGFR) and epidermal growth factor receptor (EGFR). These receptors are strongly expressed in the adult ventricular–subventricular zone (V‐SVZ), the main neurogenic niche in the adult brain. The aim of this study was to determine the cell lineage and cell fate of V‐SVZ neural progenitors expanded by phenytoin, as well as the effects of this drug on EGFR/FGFR phosphorylation. Male BALB/C mice received 10 mg/kg phenytoin by oral cannula for 30 days. We analysed the proliferation of V‐SVZ neural progenitors by immunohistochemistry and western blot. Our findings indicate that phenytoin enhanced twofold the phosphorylation of EGFR and FGFR in the V‐SVZ, increased the number of bromodeoxyuridine (BrdU)+/Sox2+ and BrdU+/doublecortin+ cells in the V‐SVZ, and expanded the population of Olig2‐expressing cells around the lateral ventricles. After phenytoin removal, a large number of BrdU+/Receptor interacting protein (RIP)+ cells were observed in the olfactory bulb. In conclusion, phenytoin enhanced the phosphorylation of FGFR and EGFR, and promoted the expression of neural precursor markers in the V‐SVZ. In parallel, the number of oligodendrocytes increased significantly after phenytoin removal.     

Localization of nerve growth factor, neurotrophin-3, and glial cell line-derived neurotrophic factor in nestin-expressing reactive astrocytes in the caudate-putamen of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated C57/Bl mice

To address the hypothesis that reactive astrocytes in the basal ganglia of an animal model of Parkinson's disease serve neurotrophic roles, we studied the expression pattern of neurotrophic factors in the basal ganglia of C57/Bl mice that had been treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to induce the degeneration of nigral dopamine neurons and parkinsonism. MPTP induced significant neuronal degeneration in the substantia nigra pars compacta as detected with Fluoro-Jade B staining, and this was accompanied by an increase in nestin-expressing astrocytes within the caudate-putamen. The number of nestin-positive reactive astrocytes in the caudate-putamen peaked within 3-5 days following MPTP treatment and then declined progressively toward the basal level by 21 days after treatment. Immunofluorescence and confocal microscopy confirmed coexpression of nestin or Ki-67 (cell proliferation marker) in glial fibrillary acid protein-positive astrocytes in the caudate-putamen. Double immunolabeling further revealed immunoreactivities for nerve growth factor (NGF), neurotrophin-3 (NT3), and glial cell line-derived neurotrophic factor (GDNF) in nestin-positive reactive astrocytes. Semiquantification of data obtained from mice 5 days after MPTP injection indicated that the majority of nestin-expressing cells expressed NGF (92%), NT3 (90%), or GDNF (86%). Our results present novel evidence of neurotrophic features among reactive astrocytes in the dopamine-depleted striatum. These nestin-expressing reactive astrocytes may therefore play neurotrophic roles in neural remodeling of the basal ganglia in Parkinson's disease.     

神经生长因子在大鼠脑损伤后血脑屏障的通透性

目的研究神经生长因子（NGF）在大鼠创伤性脑损伤后血脑屏障（BBB）中的通透性，寻找NGF通过BBB进入受伤脑组织的时间窗。方法采用液压打击造成大鼠中、重度颅脑创伤，尾静脉注射伊文蓝（EB），分别于伤后1h，3h，6h，12h，24h，72h，168h测量伤侧脑组织中的EB含量。将纯化的NGF用^125I标记，在上述时间段分别从尾静脉注射碘化NGF，用γ-counter计数仪测量伤侧脑组织的放射活性。结果重度脑创伤后EB值在伤后1h立即快速上升，并在3h达到高峰，峰值持续到72h，随后缓慢下降，在168h EB值仍较对照组明显增高。中度脑创伤后脑组织中的EB的含量在1h开始缓慢升高，6h达到高峰，峰值持续到12h随后下降，在168h基本恢复正常。重度脑创伤后脑组织中^125I—NGF在1h明显升高，在3h达到高峰，峰值持续约24h，在72h明显下降，在168h时仍比对照组高。中度脑创伤后^125I—NGF在1h脑组织中即能检测到，并缓慢升高，在6h即达到高峰，随后下降，至168h时其剂量同正常对照组相仿。结论脑创伤后BBB开放，其开放程度与颅脑创伤程度呈正相关。在脑创伤后NGF能随着BBB的开放而进入脑组织，NGF进入脑组织的量与BBB的开放程度及脑损伤程度呈正相关。     

Excess nerve growth factor in the periphery does not obscure development of whisker-related patterns in the rodent brain

We have addressed the issue of whether or not peripherally expressed nerve growth factor (NGF) influences the formation of whisker-specific patterns in the brain by regulating the survival of sensory neurons. Transgenic mice that overexpress an NGF cDNA in the skin were examined. In these animals, excess NGF expression is controlled by promoter and enhancer sequences of a keratin gene, thus restricting the higher levels of NGF expression to basal keratinocytes of the epidermis. Twice the number of trigeminal sensory neurons survive in transgenic mice as in normal animals, and a corresponding hyperinnervation of the whisker pad is noted, both around the vibrissa follicles and along the intervibrissal epidermis. However, the increased survival of sensory neurons and the enhanced peripheral projections do not interfere with the development of whisker-specific patterns in the trigeminal brainstem, in the ventrobasal thalamic complex or in the face-representation region of the primary somatosensory (SI) cortex. These results demonstrate that vibrissa-related central patterns are able to form in the virtual absence of trigeminal ganglion cell death and suggest that mechanisms other than a selective elimination of sensory neurons control the development of whisker-specific neural patterns in the brain. © 1996 Wiley-Liss, Inc.     

幼龄和老龄大鼠液压颅脑伤后NGFmRNA表达差异

目的观察幼龄和老龄大鼠颅脑损伤后神经生长因子信使RNA(nerve growth factor mRNA ,NGFmRNA)表达差异,探讨老年动物中枢神经损伤后神经功能缺失较多的病理生理机制,以及改善老年颅脑损伤预后的方法.方法采用大鼠侧方液压打击颅脑损伤模型,应用原位杂交方法和计算机显微图象分析技术,比较幼龄(2～3个月)和老龄(15个月)大鼠脑损伤后12 h脑内 NGFmRNA 表达水平的差异,并用β2 受体激动剂克仑特罗(clenbuterol,CLE)作为干预手段,观察其对幼龄和老龄大鼠受损脑组织 NGFmRNA 表达的调节作用.结果液压打击伤后12 h,两组大鼠损伤脑组织NGFmRNA表达均有不同程度的增加,但是老龄鼠损伤侧大脑皮层NGFmRNA表达明显低于幼龄鼠( P <0.05);伤后立即应用CLE(0.5 mg/kg,腹腔注射)并不提高幼龄大鼠受伤脑组织NGFmRNA的表达,但可显著提高老龄鼠NGFmRNA的表达( P <0.01).结论脑损伤早期老龄鼠NGFmRNA表达较低提示老年动物受损脑组织修复能力减低,这为我们认识临床上老年颅脑损伤后神经功能缺失较多的原因提供了帮助;CLE能够增加老龄大鼠受损脑组织NGFmRNA表达并可能由此提高老年动物的神经修复能力.     

Fibroblast growth factor stimulates the proliferation and differentiation of neural precursor cells in vitro

We have developed an in vitro culture system to study the regulation of proliferation and differentiation of neural precursor cells contained within the neuroepithelium of embryonic day 10 mice. A number of soluble growth factors have been tested for their ability to regulate these early events and, of these factors, we have found that the fibroblast growth factors [FGFs] can directly stimulate the proliferation and survival of the neuroepithelial cells. At least 50% of the neuroepithelial cells divide in the presence of FGF whereas in the absence of FGF all of the cells die within 6 days of culture. At higher concentrations of FGF, the cells change from being nonadherent round cells in tight clusters into a more flattened cell type which adheres to the substratum. This morphological change is accompanied by the expression of both neurofilament and GFAP, which are definitive markers of the two major cell types in the central nervous system: neurons and glia. In addition a neuroepithelial cell line, which does not rely on FGF for survival or proliferation, expresses both of these markers in response to FGF. These results indicate that FGF is stimulating the differentiation of the neuroepithelial cells into mature neurons and glia.     

大鼠颅脑创伤后肝细胞生长因子表达变化的实验研究

目的 探讨肝细胞生长因子(HGF)在颅脑创伤后的表达趋势,为颅脑创伤治疗中的HGF干预策略提供前期研究基础. 方法 96只wistar大鼠按随机数字表法分为实验组和假手术组,实验组为液压冲击中度颅脑创伤大鼠,并分为伤后2h、6h、12h、24 h、72h、168 h、336 h组,假手术组不致伤,每组再分为两个亚组.每亚组6只,一组行HE及免疫组化染色,观察伤后病理变化及HGF的表达部位和表达量,另外一组用RT-PCR的方法 观察创伤后HGF mRNA表达情况.结果 在创伤后的大鼠大脑皮层组织中,HGF在蛋白水平以及基因水平都出现表达增高的情况.创伤边缘区HGF阳性细胞数从伤后24 h开始增多,168 h达高峰,336 h有所下降,但仍高于伤前水平,差异有统计学意义(P<0.05).HGF mRNA表达量从创伤后72 h开始增加,168 h达高峰,与假手术组比较差异有统计学意义(P<0.05). 结论 HGF作为神经营养因子和血管生长因子,可能参与了颅脑创伤后神经元的保护和组织的修复、再生.     

脑室内注射碱性成纤维细胞生长因子治疗大鼠创伤生脑外伤的实验研究

目的 探讨脑室内注射碱性成纤维细胞生长因子(bFGF)对创伤性脑外伤大鼠是否具有治疗作用. 方法 24只成年SD大鼠按随机数字表法分为治疗组和对照组,采用改良的Feeney氏自由落体撞击方法建立大鼠创伤性脑外伤模型,致伤后24 h分别给予脑室内注射bFGF和等量的生理盐水;采用行为测试试验(前肢放置试验、平衡试验)评分观察肢体功能恢复情况;采用免疫组化法,以5溴脱氧嘧啶尿苷(Brdu)标记神经干细胞,观察并比较两组大鼠致伤后第3、7、14天侧脑室室管膜下区(SVZ)、海马齿状回及损伤区域Brdu阳性细胞的表达. 结果 治疗组前肢放置试验评分在第3～12天、平衡试验在第3～11天的评分低于对照组,比较差异有统汁学意义(P<0.05).治疗组双侧SVZ、海马齿状回和损伤区域出现的Brdu阳性细胞数较对照组明显增多,差异有统计学意义(P<0.05).两组损伤侧Brdu阳性细胞数均高于损伤对侧,比较差异有统计学意义(P<0.05).行为学评分与Brdu阳性细胞数之间呈负相关关系. 结论 脑室内注射bFGF有助于创伤性脑外伤大鼠模型内源性神经干细胞的增殖,并能促进其肢体功能的恢复.     

Effect of the N‐methyl‐D‐aspartate NR2B subunit antagonist ifenprodil on precursor cell proliferation in the hippocampus

The N‐methyl‐D‐aspartate (NMDA) receptor, one of the ionotropic glutamate receptor, plays important physiological and pathological roles in learning and memory, neuronal development, acute and chronic neurological diseases, and neurogenesis. This work examines the contribution of the NR2B NMDA receptor subunit to adult neurogenesis/cell proliferation under physiological conditions and following an excitotoxic insult. We have previously shown in vitro that a discrete NMDA‐induced, excitotoxic injury to the hippocampus results in an increase in neurogenesis within the dentate gyrus. Here we have characterized adult neurogenesis or proliferation, using BrdU, in an in vivo model of excitotoxic injury to the CA1 subfield of the hippocampus. We demonstrate a peak in neural stem cell proliferation/neurogenesis between 6 and 9 days after the excitotoxic insult. Treatment with ifenprodil, an NR2B subunit‐specific NMDA receptor antagonist, without prior injury induction, also increased the number of BrdU‐positive cells within the DG and posterior periventricle, indicating that ifenprodil itself could modulate the rate of proliferation. Interestingly, though, the increased level of cell proliferation did not change significantly when ifenprodil was administered following an excitotoxic insult. In conclusion, our results suggest and add to the growing evidence that NR2B subunit‐containing NMDA receptors play a role in neural stem cell proliferation. © 2014 Wiley Periodicals, Inc.     

Neuroprotective effect of chronic lithium treatment against hypoxia in specific brain regions with upregulation of cAMP response element binding protein and brain-derived neurotrophic factor but not nerve growth factor: comparison with acute lithium treatment

Objectives:  We evaluated the neuroprotective effect of chronically or acutely administered lithium against hypoxia in several brain regions. Furthermore, we investigated the contribution of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and cAMP response element binding protein (CREB) to the neuroprotective effect of lithium.
Methods:  Brain slices were prepared from rats that had been treated chronically or acutely with lithium. The cerebral glucose metabolic rate (CMRglc) before and after hypoxia loading to brain slices was measured using the dynamic positron autoradiography technique with [¹⁸F]2-fluoro-2-deoxy- d -glucose. The changes of expression of proteins were investigated using Western blot analysis.
Results:  Before hypoxia loading, the CMRglc did not differ between the lithium-treated and untreated groups. After hypoxia loading, the CMRglc of the untreated group was significantly lower than that before hypoxia loading. However, the CMRglc of the chronic lithium treatment group recovered in the frontal cortex, caudate putamen, hippocampus and cerebellum, but not in the thalamus. In contrast, the CMRglc of the acute lithium treatment group did not recover in any analyzed brain regions. After chronic lithium treatment, the levels of expression of BDNF and phospho-CREB were higher than those of untreated rats in the frontal cortex, but not in the thalamus. However, the expression of NGF did not change in the frontal cortex and thalamus.
Conclusions:  These results demonstrated that lithium was neuroprotective against hypoxia only after chronic treatment and only in specific brain regions, and that CREB and BDNF might contribute to this effect.     

Granulocyte colony‐stimulating factor promotes behavioral recovery in a mouse model of traumatic brain injury

Hematopoietic growth factors such as granulocyte colony‐stimulating factor (G‐CSF) represent a novel approach for treatment of traumatic brain injury (TBI). After mild controlled cortical impact (CCI), mice were treated with G‐CSF (100 μg/kg) for 3 consecutive days. The primary behavioral endpoint was performance on the radial arm water maze (RAWM), assessed 7 and 14 days after CCI. Secondary endpoints included 1) motor performance on a rotating cylinder (rotarod), 2) measurement of microglial and astroglial response, 3) hippocampal neurogenesis, and 4) measures of neurotrophic factors (brain‐derived neurotrophic factor [BDNF] and glial cell line‐derived neurotrophic factor [GDNF]) and cytokines in brain homogenates. G‐CSF‐treated animals performed significantly better than vehicle‐treated mice in the RAWM at 1 and 2 weeks but not on the rotarod. Cellular changes found in the G‐CSF group included increased hippocampal neurogenesis as well as astrocytosis and microgliosis in both the striatum and the hippocampus. Neurotrophic factors GDNF and BDNF, elaborated by activated microglia and astrocytes, were increased in G‐CSF‐treated mice. These factors along with G‐CSF itself are known to promote hippocampal neurogenesis and inhibit apoptosis and likely contributed to improvement in the hippocampal‐dependent learning task. Six cytokines that were modulated by G‐CSF treatment following CCI were elevated on day 3, but only one of them remained altered by day 7, and all of them were no different from vehicle controls by day 14. The pro‐ and anti‐inflammatory cytokines modulated by G‐CSF administration interact in a complex and incompletely understood network involving both damage and recovery processes, underscoring the dual role of inflammation after TBI. © 2016 Wiley Periodicals, Inc.