BACKGROUND:Treadmill training is one of the effective ways to promote the recovery of motor function after spinal cord injury.Treadmill training can promote neurogenesis,but the effect of different intensities of treadmill training on the activation of endogenous stem cells is still unclear. OBJECTIVE:To analyze the activation effect of different intensities of treadmill training on endogenous neural stem cells in the spinal cord of mice after spinal cord injury. METHODS:Fifty female C57BL/6J mice were divided into control group,spinal cord injury group,low-,moderate-,and high-intensity exercise groups with 10 mice in each group by random number table method.T10 segment spinal cord injury model was constructed by the clamp method in spinal cord injury group,low-,moderate-,and high-intensity exercise groups.On day 7 after spinal cord injury,mice in the low-,moderate-,and high-intensity exercise groups were respectively trained on the treadmill with corresponding intensity,3 times/d,10 min/times,6 times a week for 28 consecutive days.At 3,7,14,21,and 28 days after treadmill training,the hind limb motor function was evaluated by BMS score.At 28 days after treadmill training,the spinal cord tissue of the injured area was obtained,and the expression of epidermal growth factor receptor,glial fibrillary acidic protein,and 5-Ethynyl-2'-deoxyuridine(EdU),a proliferative marker,was detected.Hematoxylin-eosin staining was used to observe the morphology of spinal cord. RESULTS AND CONCLUSION:(1)The BMS score of mice in the spinal cord injury group was lower than that in the control group(P<0.05).With the extension of treadmill training time,the BMS scores of mice with spinal cord injury gradually increased,and the BMS scores of mice in moderate-intensity exercise group on days 14 and 21 after treadmill training were higher than those in spinal cord injury group and low-and high-intensity exercise groups(P<0.05).The BMS score of mice in moderate-and high-intensity exercise group was higher than that in spinal cord injury group and low-intensity exercise group at 28 days after treadmill training(P<0.05).(2)Compared with the control group,the proportion of epidermal growth factor receptor and EdU positive cells was increased in spinal cord injury group(P<0.05).Compared with spinal cord injury group,the proportion of epidermal growth factor receptor and EdU positive cells was increased in low-,moderate-,and high-intensity exercise groups(P<0.05),and the highest was found in moderate-intensity exercise group.Compared with control group,the proportion of glial fibrillary acidic protein positive cells was increased in spinal cord injury group(P<0.05).Compared with spinal cord injury group,the proportion of glial fibrillary acidic protein positive cells was lower in low-,moderate-,and high-intensity exercise groups(P<0.05),and the moderate-intensity exercise group was the lowest.(3)Hematoxylin-eosin staining showed that a large cavity was formed in the injured area of mice with spinal cord injury,and the cavity in the injured area of mice with spinal cord injury decreased after different intensities of treadmill training,and the decrease was most obvious in the moderate-intensity exercise group.(4)These results indicate that low-,moderate-,and high-intensity treadmill training can promote the recovery of motor function of mice with spinal cord injury by activating endogenous neural stem cells,and the effect of moderate-intensity exercise training is the most obvious.

BACKGROUND:We have successfully isolated and cultured neonatal mouse cerebrospinal fluid-contacting neurons in vitro,but there is no study that reports an effective method for isolating and culturing high-purity adult mouse cerebrospinal fluid-contacting neurons.There is no study on whether the self-renewal ability of cerebrospinal fluid-contacting neurons changes with age.OBJECTIVE:To establish a method for isolating and culturing high-purity adult mouse cerebrospinal fluid-contacting neurons in vitro,and to characterize the self-renewal ability of adult mouse cerebrospinal fluid-contacting neurons and neonatal mouse cerebrospinal fluid-contacting neurons in vitro.METHODS:Primary cells containing cerebrospinal fluid-contacting neurons were isolated from the cervical medulla of adult mouse (3 months of age) in adherent culture and transfected with lentivirus fused with multimodal imaging genes.High-purity adult mouse cerebrospinal fluid-contacting neurons were obtained by puromycin screening in suspension culture in complete medium.The expression of neural stem cell markers Nestin and SOX2 was detected by immunofluorescence in adult mouse cerebrospinal fluid-contacting neurons,and the ability of adult mouse cerebrospinal fluid-contacting neurons to form spheres and pass on in vitro was observed.An equal number (5×103/mL) of passage 3 adult mouse and neonatal mouse cerebrospinal fluid-contacting neurons were divided into two groups under the same conditions and inoculated into ultra-low adhesion plates containing complete medium in suspension culture at 5％ CO2,37℃ thermostat,respectively.The self-renewal capacity of adult mouse and neonatal mouse cerebrospinal fluid-contacting neurons was characterized by in vitro spheroid formation,CCK8 assay,qPCR,and western blot assay.RESULTS AND CONCLUSION:(1) High-purity cerebrospinal fluid-contacting neurons were successfully isolated from adult mouse,which expressed Nestin and SOX2 in vitro,and were able to form neurospheres and pass on continuously.(2) The in vitro self-renewal ability of cerebrospinal fluid-contacting neurons in adult mouse was significantly weaker than that of neonatal mouse,and the neurospheres formed by day 4 of cell culture in neonatal mouse were about 150 μm in diameter,whereas the neurospheres formed by adult mouse tactile neurons were only 40 μm in diameter (P<0.0001).(3) CCK8 proliferation assay showed that the proliferative activity of adult mouse cerebrospinal fluid-contacting neurons was significantly weaker than that of neonatal mouse at all time points after culture (P<0.0001).(4) qPCR and western blot assay revealed that the mRNA (P<0.0001) and protein expression levels (P<0.01) of Nestin and SOX2 in cerebrospinal fluid-contacting neurons of adult mouse were significantly decreased compared with those of neonatal mouse.(5) The above results indicated that the self-renewal ability of cerebrospinal fluid-contacting neurons in adult mouse was significantly weaker than that of neonatal mouse in vitro.

BACKGROUND:We have successfully isolated and cultured neonatal mouse cerebrospinal fluid-contacting neurons in vitro,but there is no study that reports an effective method for isolating and culturing high-purity adult mouse cerebrospinal fluid-contacting neurons.There is no study on whether the self-renewal ability of cerebrospinal fluid-contacting neurons changes with age.OBJECTIVE:To establish a method for isolating and culturing high-purity adult mouse cerebrospinal fluid-contacting neurons in vitro,and to characterize the self-renewal ability of adult mouse cerebrospinal fluid-contacting neurons and neonatal mouse cerebrospinal fluid-contacting neurons in vitro.METHODS:Primary cells containing cerebrospinal fluid-contacting neurons were isolated from the cervical medulla of adult mouse (3 months of age) in adherent culture and transfected with lentivirus fused with multimodal imaging genes.High-purity adult mouse cerebrospinal fluid-contacting neurons were obtained by puromycin screening in suspension culture in complete medium.The expression of neural stem cell markers Nestin and SOX2 was detected by immunofluorescence in adult mouse cerebrospinal fluid-contacting neurons,and the ability of adult mouse cerebrospinal fluid-contacting neurons to form spheres and pass on in vitro was observed.An equal number (5×103/mL) of passage 3 adult mouse and neonatal mouse cerebrospinal fluid-contacting neurons were divided into two groups under the same conditions and inoculated into ultra-low adhesion plates containing complete medium in suspension culture at 5％ CO2,37℃ thermostat,respectively.The self-renewal capacity of adult mouse and neonatal mouse cerebrospinal fluid-contacting neurons was characterized by in vitro spheroid formation,CCK8 assay,qPCR,and western blot assay.RESULTS AND CONCLUSION:(1) High-purity cerebrospinal fluid-contacting neurons were successfully isolated from adult mouse,which expressed Nestin and SOX2 in vitro,and were able to form neurospheres and pass on continuously.(2) The in vitro self-renewal ability of cerebrospinal fluid-contacting neurons in adult mouse was significantly weaker than that of neonatal mouse,and the neurospheres formed by day 4 of cell culture in neonatal mouse were about 150 μm in diameter,whereas the neurospheres formed by adult mouse tactile neurons were only 40 μm in diameter (P<0.0001).(3) CCK8 proliferation assay showed that the proliferative activity of adult mouse cerebrospinal fluid-contacting neurons was significantly weaker than that of neonatal mouse at all time points after culture (P<0.0001).(4) qPCR and western blot assay revealed that the mRNA (P<0.0001) and protein expression levels (P<0.01) of Nestin and SOX2 in cerebrospinal fluid-contacting neurons of adult mouse were significantly decreased compared with those of neonatal mouse.(5) The above results indicated that the self-renewal ability of cerebrospinal fluid-contacting neurons in adult mouse was significantly weaker than that of neonatal mouse in vitro.

Objective:To develop a nomogram predictive model on the basis of identification of the risk factors associated with failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction.Methods:A retrospective study was conducted of the clinical data of the patients who had been treated for dislocation of the subaxial cervical spine with locked facets at Department of Orthopaedic Trauma, The Hospital Affiliated to Guizhou Medical University and Department of Spine Surgery, The People's Hospital of Guizhou Province from January 2014 to December 2022. The clinical data from The Hospital Affiliated to Guizhou Medical University were used as a training set (156 cases) and those from The People's Hospital of Guizhou Province as an external validation set (54 cases). Univariate analysis and multi-variate logistic regression analysis of the training set were conducted to screen out independent risk factors associated with the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction. A nomogram predictive model was thus constructed and assessed by the receiver operating characteristic (ROC) curve, calibration curve, and decision curve. Internal validation of the training set and external validation set was used to evaluate and validate the model.Results:The multivariate logistic regression analysis revealed that cervical Ⅰ grade dislocation ( P=0.002), cervical Ⅱ grade dislocation ( P=0.007), low segment affected ( P=0.042), unilateral facet locked ( P=0.027), and the ASIA grading of spinal cord injury ( P=0.008) were the independent risk factors associated with the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction, based on which the nomogram model with a C-index of 0.88 was constructed to predict the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction. Analysis of the ROC curve of the training set showed an area under the curve (AUC) of 0.88, indicating good accuracy of the nomogram model. Analysis of the calibration curve showed high consistency between the probability of the nomogram model predicting the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction and the actual probability of traction reposition failure. Analysis of the decision curve showed that application of the nomogram model led to good benefits when the net benefit threshold for the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction was 0.03 to 0.84. Analysis of the ROC curve of external validation set showed an AUC of 0.79, indicating good accuracy of the nomogram model. The training set showed a C-index of 0.87 after 1,000 internal verifications by the Bootstrap method, indicating good discrimination of the nomogram model. Conclusions:Cervical Ⅰ grade dislocation, cervical Ⅱ grade dislocation, low segment affected, unilateral facet locked, and incomplete spinal cord injury are independent risk factors associated with failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction. A nomogram model has been successfully constructed which can predict the failure in repositioning the dislocation of the subaxial cervical spine with locked facets by skull traction. Validation and evaluation of the nomogram model have demonstrated its good predictive value.