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.

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.

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.

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.

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.

Changes in synapse quantity and growth associated protein 43 expression in the motor cortex of focal cerebral ischemic rats following catalpol treatment

The present study investigated the effects of catalpol, the main constituent of the Chinese herb Rehmannia root, on neurons following brain ischemia, A rat model of focal permanent brain ischemia was established using electrocoagulation, The rats were intrapedtoneally injected with catalpol, at a dose of 5 mg/kg, daily for 1 week, Results showed that the number of neuronal synapses in the motor cortex and growth associated protein 43 expression were increased following catalpol treatment, indicating that catalpol might contribute to neuroplasticity and ameliorate functional neurological deficits induced by cerebral ischemia.

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.

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.

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.

Effects of cyclooxygenase 2 inhibitor on growth-associated protein 43 and nerve growth factor expression in dorsal root ganglion during neuropathic pain development

BACKGROUND： Inflammatory responses in injured nerves have been recognized as important factors for initially sensitizing nociceptive neurons. Cyclooxygenase （COX） is the rate-limiting enzyme in prostaglandin synthesis, and COX-2 inhibitor is involved in mechanisms of analgesia and anti-inflammation. OBJECTIVE： To investigate the effects of COX-2 inhibitor on thermal and mechanical hyperalgesia, as well as expression of growth associated protein 43 （GAP-43） and nerve growth factor （NGF） in dorsal root ganglion, in a rat model of neuropathic pain due to chronic constriction injury. DESIGN, TIME AND SETTING： A randomized, controlled, comparison study that was performed at the Surgical Department and Pathological Laboratory, Second Affiliated Hospital of Shantou University Medical College from September 2006 to September 2007. MATERIALS： COX-2 inhibitor, Iornoxicam, was purchased from Nycomed Pharmaceutical （Austria）; rabbit anti-GAP-43, and rabbit anti-NGF polyclonal antibodies were purchased from Boster, Wuhan, China. METHODS： A total of 50 adult, Wistar rats were randomly assigned to four groups： normal control （n = 5）, model （n = 15）, normal saline control （n = 15）, and Iornoxicam treatment （n =15）. With exception of the control group, the sciatic nerve of all rats was loosely ligated to establish a model of chronic constriction injury. The model rats were divided into three subgroups according to varying post-operative survival periods： 3, 7 and 14 days （n = 5）, respectively. Rats in the Iornoxicam treatment group were intraperitoneally injected with 1.3 mg/kg lornoxicam every 12 hours throughout the entire experimental procedure. Rats in the normal saline control group were intraperitoneally injected with 1.3 mL/kg saline. MAIN OUTCOME MEASURES： Immunohistochemistry revealed expression of GAP-43 and NGF in the L5 dorsal root ganglions. Mechanical withdrawal threshold and thermal withdrawal latency were used to observe neurological behavioral changes in rats. RESULTS： The relative gray values of GAP-43- and NGF-positive neurons in the model group were remarkably increased compared with the normal control rats （P 〈 0.01）, while the relative gray values in the Iomoxicam treatment group were significantly less than the model and normal saline control groups （P 〈 0.01）. Mechanical withdrawal threshold and thermal withdrawal latency gradually decreased with increasing injury time in the model, normal saline control, and Iornoxicam treatment groups, and were significantly less than the normal control group （P 〈 0.05）. In addition, mechanical withdrawal threshold and thermal withdrawal latency were significantly greater in the Iornoxicam treatment group compared with the model and normal saline control groups （P 〈 0.05）. CONCLUSION： Intraperitoneal injection of the COX-2 inhibitor Iornoxicam attenuated mechanical and thermal hyperalgesia induced by sciatic nerve chronic constriction injury and inhibited the increased expression of GAP-43 and NGF.

Volatile of alkyd varnish inhibits the expression of neuronal growth associated protein-43 in mice

BACKGROUND： Studies have demonstrated that coating materials used commonly in the interior decoration contain volatile of alkyd varnish, which has obvious effects on the structure of endothelial cells of respiratory tract. OBJECTIVE： To observe the effects of volatile of alkyd varnish in the decoration materials on the expression of neuronal growth associated protein-43 （GAP-43） in mice, and to analyze the influencing mechanism of interior environmental pollutants for brain mechanism. DESIGN： A randomized grouping and controlled experiment. SETTING： College of Life Science, Liaoning Normal University. MATERIALS： This study was carried out in the College of Life Science, Liaoning Normal University between February and December 2006. Twenty one-month-old Kunming mice, weighing （20 ± 2 ） g, male and female in half, were involved in this study. The involved mice were divided into 2 groups by random lot method： chronic poisoning group （n =10） and control group （n =10）. Alkyd varnish used commonly for house decoration was purchased from Furnishing World of Liberation Plaza of Dalian City. Alkyd varnish used commonly for house decoration was purchased from Furnishing World of Liberation Plaza of Dalian City. Rabbit GAP-43 polyclonal antibody, rat β -actin monoclonal antibody, goat anti-rat IgG-HRP and goat ant-rabbit IgG-HRP were purchased from Boster Company （Wuhan）. ECL was purchased from Amersham Company （Britain）, other related reagents were all purchased from Sigma Company and Promega Company （USA）. All the other reagents were home-made analytical pure. METHODS： ①Poisoning test： The mice were poisoned by static inhalation poisoning method. Mice in the chronic poisoning group were placed in the 0.024 m^3 poisoning cabinet. Alkyd varnish （8 g, 3-time dosage of house decoration） was daily spread once on a 40 cm × 21 cm kraft paper evenly. Mice were poisoned for 14 hours within 3 weeks successively. Mice in the control group were placed in the same environment without alkyd varnish, and the poisoning method was the same as that of chronic poisoning group. ② Experimental evaluation： content of protein in the cortex, cerebellum and hippocampus of mice was measured separately by Bradford method. GAP-43 expression in the hippocampus and cortex was observed separately by SDS-polyacrylamide gel electrophoresis （SDS-PAGE）. MAIN OUTCOME MEASURES： Content of protein and expression of GAP-43 in different brain regions of mice. RESULTS： Twenty mice were involved in the final analysis. ① Content of protein in the cerebellum and hippocampus of mice in the chronic poisoning group was decreased a little, separately （P 〉 0.05）. ② GAP-43 expression in the hippocampus of mice of the chronic poisoning group was significantly lower than that of the control group（P 〈 0.05）. CONCLUSION： Long-term action of volatile of alkyd varnish can inhibit the brain functions of mice by depressing the GAP-43 expression in hippocampus of mice.

The43,000Growth - associated Protein Functions as a Negative Growth Regulator in Glioma.

Previous molecular analyses of human astrocytomas have identified many genetic changes associated with astrocy-toma formation and progression.In an effort to identify novel gene expression changes associated with astrocytomaformation,which might reveal new potential targets for glioma therapeutic drug design,we used the B8-RAS-transgenic mouse astrocytoma model.Using multiplex gene expression profiling,we found that

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.

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.

Inhibition of neurite outgrowth using commercial myelin associated glycoprotein-Fc in neuro-2a cells

Myelin-associated glycoprotein（MAG） inhibits the growth of neurites from nerve cells. Extraction and purification of MAG require complex operations; therefore, we attempted to determine whether commercially available MAG-Fc can replace endogenous MAG for research purposes. Immunofluorescence using specific antibodies against MAG, Nogo receptor（NgR） and paired immunoglobulin-like receptor B（PirB） was used to determine whether MAG-Fc can be endocytosed by neuro-2a cells. In addition, neurite outgrowth of neuro-2a cells treated with different doses of MAG-Fc was evaluated. Enzyme linked immunosorbent assays were used to measure RhoA activity. Western blot assays were conducted to assess Rho-associated protein kinase（ROCK） phosphorylation. Neuro-2a cells expressed NgR and PirB, and MAG-Fc could be endocytosed by binding to NgR and PirB. This activated intracellular signaling pathways to increase RhoA activity and ROCK phosphorylation, ultimately inhibiting neurite outgrowth. These findings not only verify that MAG-Fc can inhibit the growth of neural neurites by activating RhoA signaling pathways, similarly to endogenous MAG, but also clearly demonstrate that commercial MAG-Fc is suitable for experimental studies of neurite outgrowth.

Expression changes of microtubule associated protein 1B in the brain of Fmr1 knockout mice

Objective To explore the regulatory effect of fragile X mental retardation protein （FMRP） on the translation of microtubule associated protein 1B （MAP1B）. Methods The expressions of MAP1B protein and MAP1B mRNA in the brains of 1-week and 6-week old fragile X mental retardation-1 （FmrI） knockout （KO） mice were investigated by immunohistochemistry, Western blot, and in situ hybridization, with the age-matched wild type mice （WT） as controls. Results The mean optical density （MOD） of MAP1B was significantly decreased in each brain region in KO6W compared with WT6W, whereas in KO1W, this decrease was only found in the hippocampus and cerebellum. MAP1B in 6-week mice was much less than that in 1-week mice of the same genotype. The results of Western blot and in situ hybridization showed that MAP1B protein and MAP1B mRNA were significantly decreased in the hippocampus of both KO1W and KO6W. Conclusion The decreased MAP1B protein and MAP1B mRNA in the Fmrl knockout mice indicate that FMRP may positively regulate the expression of MAP1B.

The role of microtubule-associated protein 1B in axonal growth and neuronal migration in the central nervous system

In this review, we discuss the role of microtubule-associated protein 1 B （MAP1B） and its phosphorylation in axonal development and regeneration in the central nervous system. MAP1B exhibits similar functions during axonal development and regeneration. MAP1B and phosphorylated MAPIB in neurons and axons maintain a dynamic balance between cytoskeletal components, and regulate the stability and interaction of microtubules and actin to promote axonal growth, neural connectivity and regeneration in the central nervous system.

Corepressor metastasis-associated protein 3 modulates epithelial-to-mesenchymal transition and metastasis

Worldwide,metastasis is the leading cause of more than 90%of cancer-related deaths.Currently,no specific therapies effectively impede metastasis.Metastatic processes are controlled by complex regulatory networks and transcriptional hierarchy.Corepressor metastasis-associated protein 3(MTA3)has been confirmed as a novel component of nucleosome remodeling and histone deacetylation(NuRD).Increasing evidence supports the theory that,in the recruitment of transcription factors,coregulators function as master regulators rather than passive passengers.As a master regulator,MTA3 governs the target selection for Nu RD and functions as a transcriptional repressor.MTA3dysregulation is associated with tumor progression,invasion,and metastasis in various cancers.MTA3 is also a key regulator of E-cadherin expression and epithelial-to-mesenchymal transition.Elucidating the functions of MTA3 might help to find additional therapeutic approaches for targeting components of NuRD.