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 synthe...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.展开更多
Neuronal injuries such as stroke,traumatic brain injury,and spinal cord injury are leading causes of major disability and death.Chronic therapy for these neuronal injuries requires the promotion of axonal regeneration...Neuronal injuries such as stroke,traumatic brain injury,and spinal cord injury are leading causes of major disability and death.Chronic therapy for these neuronal injuries requires the promotion of axonal regeneration from the remaining neurons（Schwab and Strittmatter,2014）.展开更多
The mechanism involved in neural regeneration after spinal cord injury is unclear. The my-elin-derived protein Nogo-A, which is speciifc to the central nervous system, has been identiifed to negatively affect the cyto...The mechanism involved in neural regeneration after spinal cord injury is unclear. The my-elin-derived protein Nogo-A, which is speciifc to the central nervous system, has been identiifed to negatively affect the cytoskeleton and growth program of axotomized neurons. Studies have shown that Nogo-A exerts immediate and chronic inhibitory effects on neurite outgrowth.In vivo, inhibitors of Nogo-A have been shown to lead to a marked enhancement of regenerative axon extension. We established a spinal cord injury model in rats using a free-falling weight drop device to subsequently investigate Nogo-A expression. Nogo-A mRNA and protein expression and immunoreactivity were detected in spinal cord tissue using real-time quantitative PCR, immu-nohistochemistry and western blot analysis. At 24 hours after spinal cord injury, Nogo-A protein and mRNA expression was low in the injured group compared with control and sham-operated groups. The levels then continued to drop further and were at their lowest at 3 days, rapidly rose to a peak after 7 days, and then gradually declined again after 14 days. These changes were observed at both the mRNA and protein level. The transient decrease observed early after injury followed by high levels for a few days indicates Nogo-A expression is time dependent. This may contribute to the lack of regeneration in the central nervous system after spinal cord injury. The dynamic varia-tion of Nogo-A should be taken into account in the treatment of spinal cord injury.展开更多
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 availabl...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.展开更多
目的探讨红景天苷(salidroside,Sal)对大鼠局灶性脑缺血/再灌注损伤的神经保护作用及其机制。方法健康成年♂SD大鼠36只,随机分为3组:假手术组(sham)、模型对照组(MCAO组)、红景天苷给药组(MCAO+Sal组)。通过线栓法制作大鼠局灶性脑缺血...目的探讨红景天苷(salidroside,Sal)对大鼠局灶性脑缺血/再灌注损伤的神经保护作用及其机制。方法健康成年♂SD大鼠36只,随机分为3组:假手术组(sham)、模型对照组(MCAO组)、红景天苷给药组(MCAO+Sal组)。通过线栓法制作大鼠局灶性脑缺血/再灌注损伤模型,Longa评分法对大鼠神经功能损伤评分,焦油紫染色法对神经细胞内尼氏(Nissl)小体染色,RT-q PCR技术检测大鼠缺血侧脑组织Neun、Nogo-A与Ng R m RNA的表达,Western blot法检测大鼠缺血侧脑组织Bcl-2、Neun、BDNF、NGF、Nogo-A与Ng R蛋白的表达。结果与MCAO组比较,红景天苷能明显降低神经功能损伤,增加Nissl阳性细胞的数量,促进Bcl-2、Neun、NGF、BDNF的蛋白表达,降低Nogo-A及其受体Ng R的m RNA及蛋白表达。结论红景天苷能够降低MCAO模型大鼠神经功能损伤,增加Nissl阳性细胞数目,提高Neun的表达,具有神经保护作用,此作用是通过促进抗凋亡因子Bcl-2及神经营养因子NGF、BDNF的蛋白表达,下调轴突生长抑制因子Nogo-A及其受体Ng R的蛋白表达所实现。展开更多
基金Supported by:the Scientific Research Program of Xiamen Science and Technology Bureau,No. 3502Z20077074
文摘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.
文摘Neuronal injuries such as stroke,traumatic brain injury,and spinal cord injury are leading causes of major disability and death.Chronic therapy for these neuronal injuries requires the promotion of axonal regeneration from the remaining neurons（Schwab and Strittmatter,2014）.
基金financially supported by a grant from the Natural Science Foundation of Jiangsu Province,No.BK2011180Ordinary University Graduate Student Scientific Research Innovation Projects of Jiangsu Province,No.CXZZ13-0614,CXZZ12-0609
文摘The mechanism involved in neural regeneration after spinal cord injury is unclear. The my-elin-derived protein Nogo-A, which is speciifc to the central nervous system, has been identiifed to negatively affect the cytoskeleton and growth program of axotomized neurons. Studies have shown that Nogo-A exerts immediate and chronic inhibitory effects on neurite outgrowth.In vivo, inhibitors of Nogo-A have been shown to lead to a marked enhancement of regenerative axon extension. We established a spinal cord injury model in rats using a free-falling weight drop device to subsequently investigate Nogo-A expression. Nogo-A mRNA and protein expression and immunoreactivity were detected in spinal cord tissue using real-time quantitative PCR, immu-nohistochemistry and western blot analysis. At 24 hours after spinal cord injury, Nogo-A protein and mRNA expression was low in the injured group compared with control and sham-operated groups. The levels then continued to drop further and were at their lowest at 3 days, rapidly rose to a peak after 7 days, and then gradually declined again after 14 days. These changes were observed at both the mRNA and protein level. The transient decrease observed early after injury followed by high levels for a few days indicates Nogo-A expression is time dependent. This may contribute to the lack of regeneration in the central nervous system after spinal cord injury. The dynamic varia-tion of Nogo-A should be taken into account in the treatment of spinal cord injury.
基金supported by the National Natural Science Foundation of China,No.81171178
文摘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.
文摘目的探讨红景天苷(salidroside,Sal)对大鼠局灶性脑缺血/再灌注损伤的神经保护作用及其机制。方法健康成年♂SD大鼠36只,随机分为3组:假手术组(sham)、模型对照组(MCAO组)、红景天苷给药组(MCAO+Sal组)。通过线栓法制作大鼠局灶性脑缺血/再灌注损伤模型,Longa评分法对大鼠神经功能损伤评分,焦油紫染色法对神经细胞内尼氏(Nissl)小体染色,RT-q PCR技术检测大鼠缺血侧脑组织Neun、Nogo-A与Ng R m RNA的表达,Western blot法检测大鼠缺血侧脑组织Bcl-2、Neun、BDNF、NGF、Nogo-A与Ng R蛋白的表达。结果与MCAO组比较,红景天苷能明显降低神经功能损伤,增加Nissl阳性细胞的数量,促进Bcl-2、Neun、NGF、BDNF的蛋白表达,降低Nogo-A及其受体Ng R的m RNA及蛋白表达。结论红景天苷能够降低MCAO模型大鼠神经功能损伤,增加Nissl阳性细胞数目,提高Neun的表达,具有神经保护作用,此作用是通过促进抗凋亡因子Bcl-2及神经营养因子NGF、BDNF的蛋白表达,下调轴突生长抑制因子Nogo-A及其受体Ng R的蛋白表达所实现。
