Inhibition of Autophagy by Estradiol Promotes Locomotor Recovery after Spinal Cord Injury in Rats.

17ß-estradiol (E2) has been shown to have neuroprotective effects in different central nervous system diseases. The mechanisms underlying estrogen neuroprotection in spinal cord injury (SCI) remain unclear. Previous studies have shown that autophagy plays a crucial role in the course of nerve injury. In this study, we showed that E2 treatment improved the restoration of locomotor function and decreased the loss of motor neurons in SCI rats. Real-time PCR and western blot analysis revealed that the protective function of E2 was related to the suppression of LC3II and beclin-1 expression. Immunohistochemical study further confirmed that the immunoreactivity of LC3 in the motor neurons was down-regulated when treated with E2. In vitro studies demonstrated similar results that E2 pretreatment decreased the autophagic activity induced by rapamycin (autophagy sensitizer) and increased viability in a PC12 cell model. These results indicated that the neuroprotective effects of E2 in SCI are partly related to the suppression of excessive autophagy.

[Correlation among prevertebral hyperintensity signal, canal sagittal diameter on MRI and neurologic function of patients with cervical vertebral hyperextension injury].

OBJECTIVE: To explore the correlation among prevertebral hyperintensity (PVH), sagittal canal diameter on MRI and neurologic function of patients after cervical vertebral hyperextension injury without fracture and dislocation. METHODS: The clinical data of 100 patients with cervical vertebral hyperextension injury without fracture and dislocation were retrospectively analyzed from September 2010 to December 2013. The patients were divided into PVH group and non-PVH group according to the presence of PVH on T2-weighted magnetic resonance imaging. There were 39 patients in PVH group, including 31 males and 8 females, aged from 21 to 83 years old with an average of (58.10 ± 14.78) years; and the other 69 patients in non-PVH group, including 49 males and 12 females, aged from 32 to 77 years old with an average of (55.05 ± 10.36) years. The sagittal disc level canal diameters of subaxial cervical spine were measured on mid-sagittal magnetic resonance imaging. The age, sex, cause of injury, and the segments of spinal stenosis were recorded. American Spinal Injury Association (ASIA) impairment scale and motor score were used to evaluate the neurological status. RESULTS: The ASIA motor score of the group with PVH was 52.56 ± 31.97 while the ASIA motor score was 67.70 ± 22.83 in non-PVH group (P = 0.013). More patients with intramedullary hyperintensity signal on MRI were observed in the PVH group than in non-PVH group (P = 0.006). There was a significant positive correlation between ASIA motor score and sagittal disc level canal diameter of injury segment (P = 0.003). The neurological status was worse in patients with multi-level sagittal canal diameters below 8 mm. CONCLUSION: The PVH and the disc-level canal sagittal diameter of the injury segment are associated with neurological status. The patients with multi-level sagittal canal stenosis are vulnerable to severe cervical spinal cord injury.

[Clinical application of unilateral axis translaminar screws in upper cervical instability with vertebral artery variations].

OBJECTIVE: To investigate the clinical outcomes of the posterior C1,2 screw-rod combined with C2 unilateral translaminar screw and contralateral pedicle screw fixation and autogenous bicortical iliac crest graft fusion in treating upper cervical instability with vertebral artery variations. METHODS: From June 2008 to December 2012, the clinical data of 12 patients with upper cervical instability underwent C1 lateral mass screws-C2 unilateral laminar and contralateral pedicle screws fixation combined with autogenous bicortical iliac crest graft fusion were analyzed retrospectively. There were 8 males and 4 females with a mean age of 47.5 years (ranged, 16 to 77 years). Patients suffered from occipitocervical activity limitation of motion with pain or not, VAS was 0-7 points with an average of (3.50 +/- 2.71) points. Unilateral vertebral artery hypoplasia was demonstrated by vertebral arteriography (VAG) or CTA in all patients. Cervical X-ray and CT scans were done within 7 days after surgery in order to confirm internal fixation position. Internal fixation loosening and breakage, reduction losing, bone fusion ratio were observed during follow-up. RESULTS: No nerves and vertebral artery injuries occurred during operation. Cervical pain obviously decreased and VAS was (0.92 +/- 0.90) points. Cervical alignment of 12 patients had well-recovered by X-ray while Atlantoaxial ventral lamina cortex of 1 case was encroached by CT scan without neurological symptom. All patients were followed up for 6 months to 3 years, no internal fixation loosening and breakage, reduction losing were found. All patients obtained bone fusion in 6-12 months after operation. CONCLUSION: Posterior C1 lateral mass screws-C2 unilateral laminar and contralateral pedicle screws fixation combined with autogenous bicortical iliac crest graft fusion can achieve biomechanical stability and raise the successful rate of bone fusion, while avoiding the risk of vertebral artery injury and overcoming the insufficient of bone fusion during bilateral laminar screws placement as well. Posterior C1 lateral mass screws fixation is a safe and effective additional method in treating upper cervical instability with vertebral artery variations.