Enriched environment elevates expression of growth associated protein-43 in the substantia nigra of SAMP8 mice

An enriched environment protects dopaminergic neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine（MPTP）-induced neuronal injury, but the underlying mechanism for this is not clear. Growth associated protein-43（GAP-43） is closely associated with neurite outgrowth and axon regeneration during neural development. We speculate that an enriched environment can reduce damage to dopaminergic neurons by affecting the expression of GAP-43. This study is designed to test this hypothesis. Three-month-old female senescence-accelerated mouse prone 8（SAMP8） mice were housed for 3 months in an enriched environment or a standard environment. These mice were then subcutaneously injected in the abdomen with 14 mg/kg MPTP four times at 2-hour intervals. Morris water maze testing demonstrated that learning and memory abilities were better in the enriched environment group than in the standard environment group. Reverse-transcription polymerase chain reaction, immunohistochemistry and western blot assays showed that m RNA and protein levels of GAP-43 in the substantia nigra were higher after MPTP application in the enriched environment group compared with the standard environment group. These findings indicate that an enriched environment can increase GAP-43 expression in SAMP8 mice. The upregulation of GAP-43 may be a mechanism by which an enriched environment protects against MPTP-induced neuronal damage.

Pathological changes in the retina and growth associated protein-43 expression following treatment of intracanalicular optic nerve injury via optic canal decompression,dexamethasone or their combination

BACKGROUND： The main clinical treatments for optic nerve injury are optic canal decompression and systemic administration of hormones, but both treatments have disadvantages. OBJECTIVE： To observe the pathological changes in the retina and growth associated protein-43 （GAP-43） expression, to compare the treatment of optic canal decompression, hormones, and their combination with the intracanalicular optic nerve injury.DESIGN, TIME AND SETTING： A randomized, controlled animal study was performed at the Department of Anatomy, Weifang Medical University, China, from September 2007 to November 2008.MATERIALS： Dexamethasone （Shandong Huaxin Pharmaceutical, China） and rabbit anti-GAP-43 polyclonal antibody （Boster, China） were used.METHODS： All 36 healthy adult rabbits were randomly assigned to control group （n = 4）, simple injury group （n = 20）, and treatment group （n = 12）. Intracanalicular optic nerve injury models were established using the metal cylinder free-fall impact method. The control group was left intact. The treatment group （four rabbits in each subgroup） was treated by optic nerve decompression, dexamethasone treatment （1 mg/kg daily via two intravenous infusions, 1/5 total dose reduction every 3 days, for 14 days）, and simultaneously giving surgery and hormone treatment.MAIN OUTCOME MEASURES： Pathological changes in the retina were determined using hematoxylin-eosin staining. GAP-43 expression was detected using immunohistochemistry in the retina.RESULTS： Retina injury induced obvious pathological changes in the retina. With prolonged time after optic nerve injury, the number of retinal ganglion cells was gradually decreased, and reached the minimum on day 14 （P〈0.01）. All three treatments increased the number of retinal ganglion cells （P〈0.01）, but surgery ＋ hormone treatment was most effective. No GAP-43 cells were present in the normal retinal, but they appeared 3 days after injury, peaked 7 days after injury, and then began to decline.CONCLUSION： Intracanalicular optic nerve injury induced obvious pathological changes in the retina, including increased GAP-43 expression. Optic canal decompression and hormones improved nerve repair after injury, and their combination produced better outcomes.

Effects of continuous peripheral nerve block by tetrodotoxin on growth associated protein-43 expression during neuropathic pain development

BACKGROUND： Peripheral nerve injury may lead to neuropathic pain and cause a markedly increase expression of growth associated protein-43 （GAP-43） in the spinal cord and dorsal root ganglion, local anesthetics blocking electrical impulse propagation of nerve fibers may also affect the expression of GAP-43 in the spinal cord and dorsal root ganglion. OBJECTIVE： To determine the effects of continuous peripheral nerve block by tetrodotoxin before and after nerve injury on GAP-43 expression in the dorsal root ganglion during the development of neuropathic pain. DESIGN： A randomized controlled animal experiment. SETTINGS： Department of Anesthesiology, the Second Hospital of Xiamen City; Department of Anesthesiology, the Second Affiliated Hospital of Shantou University Medical College. MATERIALS： Thirty-five Spragne Dawley （SD） rats, weighing 200 - 250 g, were randomly divided into four groups： control group （n =5）, simple sciatic nerve transection group （n =10）, peripheral nerve block before and after sciatic nerve transection groups （n =10）. All the sciatic nerve transection groups were divided into two subgroups according to the different postoperative survival periods： 3 and 7 days （n =5） respectively. Mouse anti-GAP-43 monoclonal antibody （Sigma Co., Ltd.）, supervision TM anti-mouse reagent （HRP, Changdao antibody diagnosis reagent Co., Ltd., Shanghai）, and HMIAS-100 image analysis system （Qianping Image Engineering Company, Tongji Medical University） were employed in this study. METHODS： This experiment was carried out in the Department of Surgery and Pathological Laboratory, the Second Affiliated Hospital of Shantou University Medical College from April 2005 to April 2006. ①The animals were anesthetized and the right sciatic nerve was exposed and transected at 1 cm distal to sciatic notch. ② Tetrodotoxin 10 μg/kg was injected percutaneously between the greater trochanter and the posterior superior iliac spine of fight hind limb to block the sciatic nerve proximally at 1 hour before or 4 hours after nerve injury respectively, the injection was repeated in all the rats every 12 hours.③ At 3 or 7 days after nerve injury, immunohistochemistry and image analysis were used to evaluate the expression of GAP-43 in the dorsal root ganglions of L5 to the transected sciatic nerve, and quantitative analysis was also performed. ④ Statistical analysis was performed using one way analysis of variance followed by t test. MAIN OUTCOME MEASURE： Expression of GAP-43 in the fight dorsal root ganglions of L5. RESULTS： All the 35 SD rats were involved in the final analysis of results. In normal rats, there were very low expressions of GAP-43 in the dorsal root ganglions. In simple sciatic nerve transection rats 3 and 7 days after sciatic nerve transection, the average absorbance value of GAP-43 immunopositive neurons were significantly different from that in normal rats （t =8.806, 6.771, P 〈 0.01）. Whereas 3 and 7 days after sciatic nerve transection in rats with peripheral nerve block before and after nerve injury, the average absorbance value of GAP-43 immunopositive neurons were not significantly different from that in normal rats （P 〉 0.05）. CONCLUSION： Local anesthetic continuous peripheral nerve block before or after nerve injury can suppress nerve injury induced high expression of GAP-43 during the development of neuropathic pain.

Neurofilament 200 expression in a rat model of complete spinal cord injury following growth-associated protein-43 treatment

BACKGROUND： Growth-associated protein-43 （GAP-43） expression in the nervous system has been demonstrated to promote neural regeneration, neuronal growth and development, as well as synaptic reconstruction. Neurofilament 200 （NF200） expression could reflect degree of injury and repair in injured spinal axons. OBJECTIVE： To observe NF200 expression changes in a rat model of complete spinal cord injury following GAP-43 treatment and to explore the effects of GAP-43 following spinal cord injury. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Histology and Embryology of Kunming Medical University between March 2007 and October 2008. MATERIALS： GAP-43 and GAP-43 antibody were provided by Beijing Boao Biology, China; mouse anti-rat NF200 antibody was purchased from Chemicon, USA. METHODS： Female, 8-week-old, Sprague Dawley rats were randomly assigned into three groups following complete spinal cord injury, with 20 animals in each group： GAP-43 antibody, GAP-43, and model groups. In addition, each group was subdivided into four subgroups according to sampling time after modeling, Le., 3-, 5-, 9-, and 15-day groups, with 5 rats in each group. GAP-43 antibody or GAP-43 was injected into injury sites of the spinal cord, 5 μg/0.2 mL, respectively, twice daily for three consecutive days, followed by three additional days of injection, once daily. The model group did not receive any treatment following injury. MAIN OUTCOME MEASURES： NF200 expression in the damaged spinal area at different stages was detected by immunohistochemistry; lower limb motion function following injury was evaluated using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. RESULTS： NF200 expression was significantly reduced in the GAP-43 antibody group, compared with GAP-43 and model groups, at 3 and 5 days after spinal cord injury （P 〈 0.05）. In addition, the model group expressed significantly less NF200 than the GAP-43 group （P 〈 0.05）. BBB scores from the GAP-43 antibody and model groups were remarkably less than the GAP-43 group （P 〈 0.05）. At 9 and 15 days of injury after drug withdrawal, NF200 expression was increased in the GAP-43 antibody group, and NF200 expression and BBB scores in the GAP-43 antibody and GAP-43 groups were significantly greater than in the model group （P 〈 0.05）. In particular, the GAP-43 group exhibited greater BBB scores than the GAP-43 antibody group at day 9 （P 〈 0.05）. CONCLUSION： GAP-43 promoted NF200 expression and recovery of lower limb function. Early administration of GAP-43 antibody produced reversible nerve inhibition, which was rapidly restored following withdrawal.

Influence of chronic intermittent hypoxia on growth associated protein 43 expression in the hippocampus of young rats

This study aimed to explore the pathological change to hippocampal neurons and the expression of growth associated protein 43 in 21-day-old young rats following chronic intermittent hypoxia. Hematoxylin-eosin staining results showed varying degrees of degeneration and necrosis in hippocampal neurons depending on the modeling time. Immunohistochemistry revealed that growth associated protein 43 expression in young rats following chronic intermittent hypoxia decreased, but that levels were still higher than those of normal rats at each time point, especially 4 weeks after modeling. During 1 5 weeks after modeling, a slow growth in rat weight was observed. Experimental findings indicate that chronic intermittent hypoxia may induce growth dysfunction and necrosis of hippocampal neurons, as well as increase the expression of growth associated protein 43 in young rats.

Growth-associated protein 43 and neural cell adhesion molecule expression following bone marrow-derived mesenchymal stem cell transplantation in a rat model of ischemic brain injury

BACKGROUND： Transplantation of bone marrow-derived mesenchymal stem cells （BMSCs） improves motor functional recovery, but the mechanisms remain unclear. OBJECTIVE： To investigate expression of growth-associated protein 43 （GAP-43） and neural cell adhesion molecule following BMSC transplantation to the lateral ventricle in rats with acute focal cerebral ischemic brain damage. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment using immunohistochemistry was performed at the laboratories of Department of Neurology, Renmin Hospital of Wuhan University and Doctoral Scientific Research Work Station of C-BONS PHARMA, Hubei Province, China, from January 2007 to December 2008. MATERIALS： Monoclonal mouse anti-rat 5-bromo-2-deoxyuridine and neural cell adhesion molecule antibodies were purchased from Sigma, USA; monoclonal mouse anti-rat GAP-43 antibody was purchased from Wuhan Boster, China. METHODS： Rat models of right middle cerebral artery occlusion were established using the thread method. At 1 day after middle cerebral artery occlusion, 20μL culture solution, containing 5×10^5 BMSCs, was transplanted to the left lateral ventricle using micro-injection. MAIN OUTCOME MEASURES： Scores of neurological impairment were measured to assess neural function. Expression of GAP-43 and neural cell adhesion molecule at the lesion areas was examined by immunohistochemistry. RESULTS： GAP-43 and neural cell adhesion molecule expression was low in brain tissues of the sham-operated group, but expression increased at the ischemic boundary （P 〈 0.05）. Transplantation of BMSCs further enhanced expression of GAP-43 and neural cell adhesion molecule （P 〈 0.05） and remarkably improved neurological impairment of ischemic rats （P 〈 0.05）. CONCLUSION： BMSC transplantation promoted neurological recovery in rats by upregulating expression of GAP-43 and neural cell adhesion molecule.

Enriched environment upregulates growth-associated protein 43 expression in the hippocampus and enhances cognitive abilities in prenatally stressed rat offspring

In our previous study, we reported that prenatal restraint stress could induce cognitive deficits, which correlated with a change in expression of growth-associated protein 43 in the hippocampus. In this study, we investigated the effects of enriched environment on cognitive abilities in prenatally stressed rat offspring, as well as the underlying mechanisms. Reverse transcription-PCR and western blot assay results revealed that growth-associated protein 43 mRNA and protein levels were upregulated on postnatal day 15 in the prenatal restraint stress group. Growth-associated protein 43 expression was significantly lower in the prenatal restraint stress group compared with the negative control and prenatal restraint stress plus enriched environment groups on postnatal days 30 and 50. Morris water maze test demonstrated that cognitive abilities were noticeably increased in rats from the prenatal restraint stress plus enriched environment group on postnatal day 50. These results indicate that enriched environment can improve the spatial learning and memory ability of prenatally stressed offspring by upregulating growth-associated protein 43 expression.

Amyloid precursor protein and growth-associated protein 43 expression in brain white matter and spinal cord tissues in a rat model of experimental autoimmune encephalomyelitis

Studies have demonstrated that amyloid precursor protein （APP） expression increases in multiple sclerosis tissues during acutely and chronically active stages. To determine the relationship between axonal injury and regeneration in multiple sclerosis, an animal model of experimental autoimmune encephalomyelitis was induced using different doses of myelin basic protein peptide. APP and growth-associated protein 43 （GAP-43）, which is considered a specific marker of neural regeneration, were assessed by western blot analysis. Expression of APP and GAP-43, as well as the correlation between these two proteins, in brain white matter and spinal cord tissues of experimental autoimmune encephalomyelitis rats at different pathological stages was analyzed. Results showed that APP and GAP-43 expression increased during the acute stage and decreased during remission, with a positive correlation between APP and GAP-43 expression in brain white matter and spinal cord tissues. These results suggest that APP and GAP-43 could provide nutritional and protective effects on damaged neurons.

Effect of cyclovirobuxine D on human growth-associated protein 43 and neurocan expression in ischemic brain tissue of stroke-prone renovascular hypertensive rats

BACKGROUND： Experimental data indicate that human growth-associated protein 43 mRNA expression coincides with axonal growth during nerve ganglion development; while neurocan, secreted from astrocytes, can inhibit sprouting and elongation of the axonal growth cone. OBJECTIVE： To verify regulatory effects of cyclovirobuxine D （CVB-D） extracted from Chinese box branchlet on human growth-associated protein 43 （GAP-43）, and neurocan expression in brain tissue of stroke-prone renovascular hypertensive （RHRSP） rats, at different time points after cerebral ischemia/reperfusion. DESIGN： Randomized grouping design and controlled animal study. SETTING： This study was performed at the Center of Guangdong Hospital of Traditional Chinese Medicine （a national key laboratory） from March 2003 to September 2006. MATERIALS： 100 healthy male Sprague-Dawley rats, aged 2 3 months and weighing 90-120 g, were selected for this study. CVB-D was provided by Nanjing Xiaoying Pharmaceutical Factory （Batch number： 307701）. METHODS： The initial tip of renal arteries was clamped bilaterally for 10 weeks to establish the RHRSP model. 100 RHRSP rats were randomly divided into 4 groups： naive group （n = 10）, sham surgery group （n = 10）, CVB-D group （n = 40）, and lesion group （n = 40）. Rats in the naive group did not undergo any treatment, and cervical vessels of rats in the sham surgery group were exposed, but not blocked. The right middle cerebral artery of rats in the CVB-D group and lesion group were occluded to establish cerebral ischemia. Rats in the CVB-D group were intraperitoneally injected with CVB-D （6.48 mg/kg） every day and with saline （1.5 mL/injection） twice a day. Rats in the lesion group were intraperitoneally injected with saline （2 mL/injection）. MAIN OUTCOME MEASURES： Immunohistochemistry was applied to detect GAP-43 and neurocan expression in the ischemic penumbra region of CVB-D and lesion brains at 2 hours post-cerebral ischemia and at 1, 7, 14, and 30 days post-perfusion （n = 10 at each time point）. Similarly, GAP-43 and neurocan expression was detected in the right hemisphere of naive and sham-operated animals. The results were expressed as positive cells. RESULTS： A total of 100 rats were included in the final analysis. The number of GAP-43 positive cells increased in the CVB-D group 1, 7, 14, and 30 days post-cerebral ischemia/perfusion compared to the lesion group, as indicated by a significant difference between the CVB-D and lesion group （P 〈 0.054）.01）. The number of neurocan-positive cells decreased in the CVB-D group on the first day compared to the model group; however, there was no significant difference between the two groups （P 〉 0.05）. On post-ischemia days 7, 14, and 30, the number of neurocan-positive cells in the CVB-D group was significantly less than in the lesion group （P 〈 0.05）. Both, GAP-43 and neurocan expression was not detectable in brains of naive and sham-operated animals. CONCLUSION： CVB-D treatment up-regulated GAP-43 expression and down-regulated neurocan expression in the ischemic region of RHRSP rats.

Granulocyte colony-stimulating factor promotes growth of processes,growth associated protein 43 and microtubule-associated protein 2 expression in cultured rat retinal ganglion cells in vitro

Following granulocyte colony-stimulating factor （G-CSF） treatment,the growth of processes in cul-tured rat retinal ganglion cells （RGCs） in vitro,expression of growth associated protein 43,and expression of microtubule-associated protein 2 mRNA expression were significantly increased.In contrast,RhoA/Rock protein content was significantly reduced by G-CSF treatment.These results indicate that G-CSF promotes the growth of processes in RGCs and increases the expression of growth-associated protein 43 and microtubule-associated protein 2 mRNA by inhibiting the RhoA/Rock pathway,thereby benefiting axonal repair in RGCs exposed to hypoxia.

Activation of Growth-associated Protein by Intragastric Brazilein in Motor Neuron of Spinal Cord Connected with Injured Sciatic Nerve in Mice

The purpose of this study is to explore the expression of growth-associated protein（GAP-43） in spinal cord segments connected with injured sciatic nerve by the treatment with brazilein in mice. Unilateral sciatic nerve interruption and anastomosis were performed. Physiological saline（blank group）, high dose, middle dose and low dose of brazilein were administrated intragastrically to healthy adult BALB/c mice in separate groups. L4―6 spinal segments connected with the sciatic nerve were harvested. Real-time PCR（Polymerase chain reaction） and Western blot analysis were performed to detect the expression of GAP-43 in spinal segments. Histological staining on myelin and the electrophysiology were performed to examine the sciatic nerve recovery. GAP-43 was activated in spinal cord L4―6 connected with injured sciatic nerve. In the survival time of 12 h, 24 h, 3 d, 5 d, 7 d and 14 d, GAP-43 expression in the motor neurons of spinal cord of the high dose group and that in the middle dose group were significantly higher than those on the low dose and blank groups. Myelin in the high dose group and that in the middle dose group were more mature and the potential amplitude and MNCV（motor nerve conduction velocity） in the high and middle dose groups were obviously higher than those in the low dose group and blank group. Brazilein facilitates the expression of GAP-43 in neurons in spinal cord L4―6 segments connected with injured sciatic nerve, which promotes nerve regeneration.

Preemptive analgesic effects of low-dose ketamine on growth-associated protein expression in dorsal root ganglion of chronic constriction injury model rats

BACKGROUND： Ketamine is a noncompetitive N-methyl-D-aspartate （NMDA） receptor antagonists and plays an important role in the treatment of pain. OBJECTIVE： To analyze the preemptive analgesic effects of different doses of ketamine on growth-associated protein-43 （GAP43） expression in dorsal root ganglion in a rat model of chronic sciatic nerve constricted injury, and to study the differences between high-dose and low-dose ketamine DESIGN： Randomized controlled animal study. SETTING： Medical College of Shantou University. MATERIALS： Thirty-five adult male Sprague Dawley rats were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. Ketamine hydrochloride injection was provided by Hengrui Pharmaceutical Co., Ltd., Jiangsu. METHODS： This study was performed at the Immunological Laboratory, Medical College of Shantou University from September to December 2006. Model of chronic sciatic nerve constricted injury： after anesthesia, the right sciatic nerve was exposed and ligated l-cm distal to the ischiadic tuberosity with a No. 3-0 cat gut suture. Grouping and intervention： 35 rats were randomly divided into 4 groups： normal control group （n = 5）, chronic constriction injury （CCI） group （n = 10）, low-dose ketamine group （n = 10）, and high-dose ketamine group （n = 10）. Rats in the normal control group did not undergo any surgery or drug intervention. Rats in the CCI group received intraperitoneal injection of saline （1 mL）, and their sciatic nerves were ligated after 10 minutes. Rats in the low-dose ketamine group underwent intraperitoneal injection of ketamine （25 mg/kg） 10 minutes prior to ligation of sciatic nerve; while, rats in the high-dose ketamine group were given intraperitoneal injection of ketamine （50 mg/kg） 10 minutes prior to ligation of sciatic nerve. On the third and the seventh days after surgery, dorsal root ganglion were resected from the sciatic nerve and cut into sections. MAIN OUTCOME MEASURES： GAP-43 expression in dorsal root ganglion was detected by immunohistochemistry and image analysis system, as well as semi-quantitative analysis. RESULTS： Thirty-five Sprague Dawley rats were included in the final analysis. Qualitative analysis： GAP-43 expression in the CCI group was higher than in the normal control group. Quantitative analysis： after three post-operative days, GAP-43 expression in the CCI group was significantly higher than in the normal control group （t = 22.919, 7.319, P 〈 0.05）. GAP-43 expression in the low-dose and high-dose ketamine group was significantly lower than in the CCI group （t = 11.166, 26.474, P 〈 0.05）. After seven postoperative days, GAP-43 expression in the low-dose and high-dose ketamine groups was significantly lower than in the CCI group （t = 2.382, 5.016, P 〈 0.05）. CONCLUSION： Preoperative administration of ketamine inhibited the increased GAP-43 expression in dorsal root ganglion during neuropathic pain.

不同强度白噪声建立噪声性耳鸣动物模型效果比较及对听皮层生长相关蛋白-43表达的影响

目的探究适宜的噪声性耳鸣动物模型构建方法及生长相关蛋白-43(growth associated protein,GAP-43)在耳鸣产生中的作用。方法将54只C57小鼠随机分为对照组、BBN-90dB实验组,BBN-100dB实验组,各组18只。这3组在噪声暴露后3 d、7 d、14 d进行听觉惊跳反射间隔前刺激抑制(GPIAS)检测,每组6只。分别采用90dB SPL、100dB SPL宽频带白噪声对BBN-90dB实验组、BBN-100dB实验组的C57小鼠进行单次噪声暴露2 h,随后按照时间点进行GPIAS检测以判断是否出现耳鸣行为。在检测结束后3 d组、7 d组及14 d组采用Western Blot方法检测各组听皮层中GAP-43表达变化。结果与对照组相比,在90dB SPL宽频带白噪声的条件下,C57小鼠的GPIAS%值在噪声暴露后3 d、7 d、14 d均降低(P<0.05)。但100dB SPL宽频带白噪声使C57小鼠的GPIAS%值较前者下降更为显著(P<0.01)。听皮层GAP-43表达较同期对照组而言,在噪声暴露后3 d、14 d于BBN-90dB组中呈升高趋势(P<0.05),在BBN-100dB组中于噪声暴露后3 d、7 d、14 d升高更为明显(P<0.01)。结论100dB SPL宽频带白噪声可能更适合高效、便捷地构建噪声性耳鸣动物模型,同时噪声可能通过上调GAP-43的表达,对耳鸣发生发展产生影响。

梓醇上调GAP-43表达伴随局灶脑缺血大鼠神经功能恢复

目的观察滋阴中药地黄的主要活性成分梓醇对局灶脑缺血大鼠神经功能恢复及缺血周围区大脑皮质生长相关蛋白-43表达的影响。方法♂SD大鼠42只,随机分为假手术组、模型组、生理盐水组、梓醇低、中、高剂量治疗组(剂量分别为1、5、10mg.kg-1)和胞二磷胆碱(剂量为0.4g.kg-1)对照组,每组6只。采用开颅电凝右侧大脑中动脉的方法制备局灶脑缺血模型。造模后6h,经腹腔注射首次给予梓醇进行干预,每天1次,连续7d。给药前及术后1、4、7及15d分别评定各组大鼠姿势反射及肌力变化,并在术后15d断头取脑,制备脑片和脑组织匀浆,采用免疫荧光组织化学染色和Western blot检测缺血周围区大脑皮质GAP-43蛋白表达。结果假手术组无明显神经功能障碍;梓醇高、中剂量治疗组姿势反射及肌力恢复明显优于模型组、生理盐水组和胞二磷胆碱组,且梓醇各剂量治疗组缺血周围区GAP-43蛋白表达比其它实验组明显上调(P<0.05)。结论梓醇可上调脑缺血大鼠缺血周围区皮质GAP-43表达,促进轴突再生,加速其神经功能恢复。

大鼠脑缺血/再灌注后bFGF和GAP-43的表达与神经再生

目的:观察大鼠脑缺血/再灌注后不同时间段碱性成纤维生长因子(bFGF)和生长相关蛋白43(GAP-43)表达与神经元再生的变化,探讨其与神经再生的有关机制。方法:建立大鼠大脑中动脉阻塞模型(MCAO),并分为缺血再灌注3 d、7 d、14 d和28 d四组(n=6)。以神经损伤严重程度评分(NSS),运动评分测试(SMT)评估神经功能缺损程度,Nissl和TUNEL染色法观察不同时段缺血区周边组织神经元存活和凋亡情况,应用蛋白免疫印迹法和免疫荧光双标法检测缺血/再灌注后不同时段缺血区周边组织bFGF和GAP-43的表达水平和神经元再生的变化情况。结果:大鼠脑缺血/再灌注后3 d,大鼠出现了明显的神经功能缺损及运动功能障碍,缺血区周边组织神经元凋亡亦达到高峰,同时bFGF和GAP-43表达增强,7 d达到高峰,以后逐渐减弱,缺血周边组织可见散在的新生神经元,持续到28 d。结论:大鼠脑缺血/再灌注后内源性bFGF和GAP-43表达水平增加,可能与其神经修复和再生有关。

电针对局灶性脑缺血再灌注大鼠神经生长相关蛋白-43和Nogo-A表达的影响

目的探讨电针对局灶性脑缺血再灌注模型大鼠神经功能恢复和脑组织神经生长相关蛋白-43(GAP-43)、Nogo-A表达的影响。方法 48只健康成年雄性Sprague-Dawley大鼠分为假手术组、模型组和电针组,每组16只。采用线栓法制作大鼠大脑中动脉缺血再灌注模型。电针组于造模成功90 min后电针刺双侧内关、水沟、三阴交和百会30 min,每天1次。假手术组和模型组不进行任何干预治疗。各组大鼠在造模后7 d、14 d各取8只进行神经功能评估及免疫组化SP法观察脑组织GAP-43、Nogo-A的表达。结果假手术组大鼠无神经功能缺损症状;7 d时,模型组和电针组神经功能评分无显著性差异(P>0.05),14 d时,电针组神经功能优于模型组(P<0.05)。假手术组各时间点未见GAP-43阳性细胞表达。7 d时,模型组缺血灶周围脑组织出现GAP-43阳性细胞,14 d时减少;电针组GAP-43阳性细胞各时间点较模型组明显增加(P<0.01)。假手术组仅见少量Nogo-A表达,模型组脑缺血区7 d、14 d时Nogo-A表达明显增多(P<0.01),电针组Nogo-A表达在各时间点较模型组明显减少(P<0.01)。结论电针能通过促进局灶性脑梗死大鼠脑组织内GAP-43表达、抑制Nogo-A表达,改善大鼠的神经功能。

运动训练对出血性脑损伤GAP-43基因及蛋白表达的影响

目的:观察运动训练对脑出血大鼠生长相关蛋白(GAP-43)基因及其蛋白表达的影响。方法:实验动物用健康雄性SD大鼠160只。先将96只大鼠随机分为3组,实验组(出血后运动,n=32)、对照组(出血后不运动,n=32)、假手术组(无出血不运动,n=32)。各组又分为术后第7天,第14天,第21天,第28天共4个时相点,每个时相点4只用于免疫组化检测,4只用于RT-PCR检测。实验组大鼠于术后第72小时开始跑笼训练,其余大鼠在标准笼内自由活动。再将另外64只随机分为脑出血后第6小时,第12小时,第24小时,第48小时,第72小时,第7天,假手术组和正常组,每组4只分别用于免疫组化和RT-PCR检测。结果:①免疫组化结果:GAP-43阳性细胞表达为细胞胞浆着棕黄色,阳性细胞主要分布于血肿周围和大脑皮质的神经元,实验组于脑出血后第12小时开始上调,持续到第7天,与正常组和假手术组相比差异有显著性(P<0.05)。实验组于运动后第14天出现上调,第28天达高峰,与对照组相比差异有显著性(P<0.05),实验组和对照组与假手术组相比差异有显著性(P<0.01)。②RT-PCR结果:脑出血后第12小时GAP-43 mRNA表达一度升高,与对照组比差异有显著性(P<0.05),之后维持较高水平,直到第14—28天。实验组表达于第14—28天与假手术组相比差异有显著性(P<0.05),与对照组比(P>0.05)。结论:GAP-43参与了脑出血后神经可塑性的发生,运动训练可促进GAP-43基因及蛋白表达,从而改善神经功能。

运动训练对血管性痴呆大鼠学习记忆能力及大脑皮质区生长相关蛋白-43表达的影响

目的:研究运动训练对血管性痴呆大鼠学习记忆功能恢复及组织生长相关蛋白(GAP-43)表达的影响。方法:采用双侧颈总动脉反复缺血再灌注加降血压法制作血管性痴呆大鼠模型。选择SD雌性大鼠44只,随机分为运动组20只,制动组20只和假手术组4只。运动组大鼠进行滚筒、转棒训练,1h/d;制动组大鼠限制其自由活动;假手术组置于普通笼中自由活动。3组分别于术后第27、28天进行跳台实验测定学习、记忆能力。取脑组织采用免疫组织化学染色方法观察不同时间点大脑皮质区GAP-43的表达。结果:跳台实验对学习记忆能力进行评估,运动组优于制动组(P<0.01),运动组GAP-43在皮质区的表达第1天逐渐增高,第7天达高峰,较制动组和假手术组均有明显增加(P<0.01)。结论:运动训练可改善VD大鼠学习记忆能力,其机制可能与运动训练能促进皮质区上GAP-43表达有关。

大鼠坐骨神经损伤与再生中GAP－43表达的实验研究

用免疫组化技术对６０只大鼠坐骨神经切断、卡压和再卡压损伤后不同时期的ＧＡＰ－４３表达作了观察．观察结果：（１）大鼠坐骨神经卡压或切断后，前角运动神经元、后根神经节细胞和坐骨神经纤维均产生免疫反应阳性，其中７ｄ组近段和１４ｄ组远段坐骨神经纤维为强阳性，（２）３０ｄ组各部免疫反应减弱，６０ｄ组基本恢复正常；（３）３０和６０ｄ组的再卡压损伤的各部均较同期其他损伤组免疫反应为强；（４）伤侧腰骶髓前角运动神经元染色逐渐减弱．ＧＡＰ－４３免疫反应结果显示，神经元胞体部分随再生期延长而逐渐减弱，周围部由近至远逐渐增强，又逐渐恢复至正常水平．结果提示ＧＡＰ－４３主要由神经元胞体所产生，随轴突逐渐转运至损伤和再生处，表明了此种蛋白参与神经再生，在神经再生过程中一直起着重要的作用．

神经干细胞移植对大鼠脊髓损伤后胶质细胞源性神经营养因子与生长相关蛋白43基因表达的影响

目的研究海马源性神经干细胞(neuralstemcells,NSCs)移植对大鼠脊髓损伤(spinalcordinjury,SCI)后胶质细胞源性神经营养因子(glialcellline-derivedneurotrophicfactor,GDNF)及生长相关蛋白43(growth associatedprotein43,GAP-43)基因表达的影响,探讨NSCs移植修复大鼠脊髓损伤的机制。方法新生一日龄Wistar大鼠6只,提取海马区NSCs,进行培养及鉴定。Wistar成年大鼠以改良Allen打击装置制成SCI模型。将Wistar大鼠60只分为3组:A组NSCs移植(n=24)、B组单纯损伤DMEM填充(n=24)、C组正常对照组(n=12)。于术后第1、3及7天应用RT-PCR法观察,各组大鼠脊髓区GDNF和GAP-43基因表达的变化。结果移植术后第1天,A组GDNF mRNA的表达量较B组平均增加23.3%;第3天,较B组平均增加26.8%;第7天,较B组平均增加32.7%。移植术后第1天,A组GAP-43mRNA的表达量较B组平均增加19.5%;第3天,较B组平均增加21.6%;第7天,较B组平均增加23.1%。A组较B组明显增强了GDNFmRNA和GAP-43mRNA的表达,组间差异均具有统计学意义(P<0.05)。C组各时间点GDNF及GAP-43mRNA的表达量差异无统计学意义(P>0.05)。结论NSCs移植后改变脊髓损伤区局部的微环境,上调GDNFmRNA,促进GAP-43mRNA的表达,是修复脊髓损伤的机制之一。