Chronic Exposure to Hypoxia Inhibits Myelinogenesis and Causes Motor Coordination Deficits in Adult Mice / 神经科学通报·英文版

Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults, but the underlying mechanisms remain largely unknown. Since active myelinogenesis persists in the adult central nervous system, here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice. Using a transgenic approach to label newly-generated myelin sheaths (NG2-CreER

Chronic Exposure to Hypoxia Inhibits Myelinogenesis and Causes Motor Coordination Deficits in Adult Mice / 神经科学通报·英文版

Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults, but the underlying mechanisms remain largely unknown. Since active myelinogenesis persists in the adult central nervous system, here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice. Using a transgenic approach to label newly-generated myelin sheaths (NG2-CreER

The effects of rolipram on neurofunction and the ultrastructure of the spinal cord after spinal cord contusion / 中华物理医学与康复杂志

Objective To investigate the effects of rolipram on neurofunction and the ultrastructure of the spinal cord in rats with spinal cord contusion.Methods Thirty adult,female Sprague-Dawley (SD) rats received spinal cord contusion at the T10 level.They were then randomited into an experimental group and a control group immediately after the operation.Rats in the experimental group received subcutaneous injections of 0.25mg/kg of rolipram twice daily for two weeks.Control rats received the same dosage of 0.9％ sodium chloride solution on the same schedule.The rats'functional recovery was evaluated using the open-field locomotion rating scale of Basso,Beattie and Bresnahan (BBB score),once a week within the 1st month after spinal cord injury (SCI),and once every two weeks subsequently.The morphology of the spinal cord tissue around the lesion site was observed under the light microscope with HE staining at the 8th week postoperation,and the ultrastructure of the spinal cord was observed under the transmission electron microscope at the 2nd,4th and 8th week postoperation.Results At the 2nd and 3rd week after SCI the experimental group exhibited significandy greater improvement in average BBB scores than the control group.However,the average BBB scores in the experimental and control groups were not significantly different at 8 weeks after SCI.Under the light microscope,cavities were observed in the posterior dorsal column near the SCI in both the experimental and control groups.However thick,condensed glial scars in the injured area were observed only in the control group.The density of glial cells decreased more in the experimental group than in the control group.Transmission electron microscopy revealed that,compared with the control group,inflammatory edema was attenuated and fewer axons were damaged at the 2nd week postoperation in the experimental group.That group also showed less axon degeneration as well as more angiogenesis at the 4th and 8th week.Conclusion Rolipram can reduce secondary neuron degeneration,inhibit gliosis and the formation of glial scars,and promote angiogenesis.

The effect of olfactory ensheathing cell transplantation combined with walking training on neurofunction recovery in rats after spinal cord contusion / 中华物理医学与康复杂志

Objective To explore the effect of olfactory ensheathing cell (OEC) transplantation combined with walking training on neurofunction recovery in rats after spinal cord contusion. Methods Forty adult female rats aged (75 ± 1 ) days were subjected to experimental spinal cord contusion at the T10 level using a New York University impactor at a height of 25 mm. They were then divided into 4 groups: ( 1 ) an OEC transplantation combined with walking training (OEC-walking training) group, (2) an OEC transplantation (OEC) group, (3) a walking training combined with Dulbecco's modified Eagle medium injection (DMEM) (walking training-DMEM) group, and (4) aDMEM injection (SCI-DMEM) group. The OEC transplants and DMEM injections were performed 2 weeks post-injury. Walking training began at the 7th day post-injury and consisted of daily sessions (once daily, 5 days a week for 10 weeks) of quadrupedal treadmill training, starting from 15 min and gradually increasing to 30 min daily, at speeds starting from 3 m/min and gradually increasing in accordance to the condition of the rats. Locomotor function recovery of the rats' hindlimbs was evaluated weekly using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale.The expression of tyrosine hydroxylase ( TH ) was detected in the injured region of the lumbar spinal cord. Results The BBB scores of rats in the OEC-walking training group and the walking training-DMEM group improved significantly from the 4th week post-injury compared to the SCI-DMEM injection group. Rats in the OEC transplantation group had a significant improvement in BBB scores at the 5th to 8th weeks post-injury. At the end of the 11th week post-injury, the average BBB scores were 13.14 ± 0.24 in the OEC-walking training group, 11. 64 ± 0.56 in the OEC transplantation group, 12.29 ±0.64 in the walking training-DMEM group and 11.07 ± 0.84 in the SCI-DMEM group.The OEC-walking training group scored significantly higher than the other 3 groups. Although the number of TH-positive neurons in the lumbar spinal cord was not significantly different among the groups, the morphology of TH-positiveneurons in the OEC-walking training group and the walking training-DMEM group was different from those in the OEC transplantation group and the SCI-DMEM group. Conclusions OEC transplantation combined with walking training can effectively promote the functional recovery of the hindlimb. The plasticity of the descending TH system and of motoneurons of the ventral horn of the lumbar spinal cord might mediate the changes.