Résumé
Objective:The activation of astrocytes is an important process in the formation of chronic pain.This study aims to observe the activation of A1 reactive astrocytes in the medullary dorsal horn in the rat model of trigeminal neuralgia,and to explore the mechanism of central sensitization caused by A1 reactive astrocyte. Methods:The adult male rats were randomly divided into a sham group and a chronic constriction injury of infraorbital nerve(ION-CCI)group.The facial mechanical pain threshold and thermal withdrawal latency were measured before the operation and on the 1st,3rd,7th,10th,and 14th day after the operation.After pain behavior observation,the expression of glial fibrillary acidic protein(GFAP)in the medullary dorsal horn was observed by immunohistochemistry and immunofluorescence colocalization of GFAP,complement 3(C3)/S100A10,and 4',6-diamidino-2-phenylindole(DAPI)was analyzed.Primary astrocytes were cultured and randomly divided into a naive group and a DHK group.The DHK group was treated with 1 mmol/L of astrocyte activation inhibitor dihydrokainic acid(DHK).Fura-2/AM was used to stain the astrocytes and the calcium wave of the 2 groups under the stimulation of high potassium was recorded and compared.The expression of C3 was detected by Western blotting. Results:The facial mechanical pain threshold and thermal withdrawal latency of the ION-CCI group were significantly lower than those of the sham group(both P<0.05).There were a large number of GFAP positive astrocytes in the medullary dorsal horn of the ION-CCI group.The fluorescence intensity of GFAP in the ION-CCI group was higher than that in the sham group(P<0.05).GFAP and C3/S100A10 were co-expressed in astrocytes.Compared with the sham group,the fluorescence intensity of C3 and the protein expression of C3 in the ION-CCI group were increased(both P<0.05).The expression of C3 in ION-CCI group was significantly increased(P<0.05).Compared with the naive group,the C3 protein expression was significantly decreased in the DHK group(P<0.05).The intensity of calcium fluorescence was increased after high potassium stimulation in both groups.Furthermore,the peak and increase amplitude of calcium fluorescence in the naive group were much higher than those in the DHK group(both P<0.05). Conclusion:A1 reactive astrocytes in the medullary dorsal horn of trigeminal neuralgia model rats are increased significantly,which may participate in central sensitization of trigeminal neuralgia by impacting astrocyte calcium wave.
Résumé
Objective To investigate the effects of resveratrol (Res) on motor function and the anterior horn neuron of lumbar spinal cord after acute sciatic nerve compression injury in rats.Methods The rat model with acute sciatic nerve compression injury was established in 32 Sprague Dawley (SD) rats,which were randomly divided into four groups:Res group,Dimethyl Sulfoxide (DMSO) group,Normal Saline (NS) group and sham-operation group.Res,DMSO and saline were successively injected by intraperitoneal for 10 days after established crush acute sciatic nerve compression injury model,while sham-operation group was sutured only after exposure to the sciatic nerve.The weight,the change of toe extension angle,and the sciatic functional index (SFI) of rats were observed at the 1st day before operation and the 1st,3rd,7th,and 10th days after surgery.The expressions of neuron-specific nuclear protein (NeuN) and microtubule-associate protein 2 (MAP2) were detected by immunofluorescent staining of I4-L6 spinal cord anterior horn on the 10th day after surgery.Results No significant changes were found in the weight of rats among four groups.Compared to the sham,the motor function of the injured limb in Res,DMSO,and NS rats was impaired,and the anterior horn neurons were seriously damaged.But the differences of the change of toe extension and the sciatic functional index of rats were significantly higher in Res group than that of the DMSO group and NS group (P ＜ 0.01) at the 3rd,7th,and 10th days after surgery.The expressions of NeuN and MAP2 in the anterior horn of rat lumbar spinal cord were up-regulated in Res group relative to DMSO and NS,and the number of neurons in the lumbar spinal cord was significantly relieved at the 10th days.Conclusions Res was significant to rat model of acute sciatic nerve injury,which could increase the number of neurons in the anterior horn of the spinal cord and help the recovery of motor function.
Résumé
Objective To investigate the effects of resveratrol (Res) on motor function and the anterior horn neuron of lumbar spinal cord after acute sciatic nerve compression injury in rats.Methods The rat model with acute sciatic nerve compression injury was established in 32 Sprague Dawley (SD) rats,which were randomly divided into four groups:Res group,Dimethyl Sulfoxide (DMSO) group,Normal Saline (NS) group and sham-operation group.Res,DMSO and saline were successively injected by intraperitoneal for 10 days after established crush acute sciatic nerve compression injury model,while sham-operation group was sutured only after exposure to the sciatic nerve.The weight,the change of toe extension angle,and the sciatic functional index (SFI) of rats were observed at the 1st day before operation and the 1st,3rd,7th,and 10th days after surgery.The expressions of neuron-specific nuclear protein (NeuN) and microtubule-associate protein 2 (MAP2) were detected by immunofluorescent staining of I4-L6 spinal cord anterior horn on the 10th day after surgery.Results No significant changes were found in the weight of rats among four groups.Compared to the sham,the motor function of the injured limb in Res,DMSO,and NS rats was impaired,and the anterior horn neurons were seriously damaged.But the differences of the change of toe extension and the sciatic functional index of rats were significantly higher in Res group than that of the DMSO group and NS group (P ＜ 0.01) at the 3rd,7th,and 10th days after surgery.The expressions of NeuN and MAP2 in the anterior horn of rat lumbar spinal cord were up-regulated in Res group relative to DMSO and NS,and the number of neurons in the lumbar spinal cord was significantly relieved at the 10th days.Conclusions Res was significant to rat model of acute sciatic nerve injury,which could increase the number of neurons in the anterior horn of the spinal cord and help the recovery of motor function.
Résumé
Objective To investigate the effect of intrathecal injection of lentiviral vector-mediated up-regulation of glial cell line-derived neurotrophicfactor (GDNF) on neuropathic pain of chronic constriction injury (CCI) rats.Methods The CCI model was prepared by ligating the sciatic nerve of Sprague-Dawley (SD) rats.Seven days after CCI modeling,a single intrathecal injection of lentiviral vectors (LV)-GDNF was given.Before CCI and 3,5,7,14,and 21 days after CCI modeling,the mechanical pain threshold was tested in rats,and 21 days after surgery,Western blot was used to detect the expression of GDNF protein.Results On 21 days after CCI modeling,GDNF expression was reduced compared to sham group.After intrathecal injection of LV-GDNF,GDNF expression was up-regulated in the spinal cord,and CCI-induced mechanical hyperalgesia in rats was alleviated.Conclusions Intrathecal injection LV-GDNF can up-regulate the expression of GDNF and alleviate neuropathic pain in CCI rats.