Neuroprotective effect of deferoxamine on erastininduced ferroptosis in primary cortical neurons.

The iron chelator deferoxamine has been shown to inhibit ferroptosis in spinal cord injury. However, it is unclear whether deferoxamine directly protects neurons from ferroptotic cell death. By comparing the survival rate and morphology of primary neurons and SH-SY5Y cells exposed to erastin, it was found that these cell types respond differentially to the duration and concentration of erastin treatment. Therefore, we studied the mechanisms of ferroptosis using primary cortical neurons from E16 mouse embryos. After treatment with 50 µM erastin for 48 hours, reactive oxygen species levels increased, and the expression of the cystine/glutamate antiporter system light chain and glutathione peroxidase 4 decreased. Pretreatment with deferoxamine for 12 hours inhibited these changes, reduced cell death, and ameliorated cellular morphology. Pretreatment with the apoptosis inhibitor Z-DEVD-FMK or the necroptosis inhibitor necrostain-1 for 12 hours did not protect against erastin-induced ferroptosis. Only deferoxamine protected the primary cortical neurons from ferroptosis induced by erastin, confirming the specificity of the in vitro ferroptosis model. This study was approved by the Animal Ethics Committee at the Institute of Radiation Medicine of the Chinese Academy of Medical Sciences, China (approval No. DWLL-20180913) on September 13, 2018.

Mechanisms underlying the promotion of functional recovery by deferoxamine after spinal cord injury in rats.

Deferoxamine, a clinically safe drug used for treating iron overload, also repairs spinal cord injury although the mechanism for this action remains unknown. Here, we determined whether deferoxamine was therapeutic in a rat model of spinal cord injury and explored potential mechanisms for this effect. Spinal cord injury was induced by impacting the spinal cord at the thoracic T10 vertebra level. One group of injured rats received deferoxamine, a second injured group received saline, and a third group was sham operated. Both 2 days and 2 weeks after spinal cord injury, total iron ion levels and protein expression levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1ß and the pro-apoptotic protein caspase-3 in the spinal cords of the injured deferoxamine-treated rats were significantly lower than those in the injured saline-treated group. The percentage of the area positive for glial fibrillary acidic protein immunoreactivity and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells were also significantly decreased both 2 days and 2 weeks post injury, while the number of NeuN-positive cells and the percentage of the area positive for the oligodendrocyte marker CNPase were increased in the injured deferoxamine-treated rats. At 14-56 days post injury, hind limb motor function in the deferoxamine-treated rats was superior to that in the saline-treated rats. These results suggest that deferoxamine decreases total iron ion, tumor necrosis factor-α, interleukin-1ß, and caspase-3 expression levels after spinal cord injury and inhibits apoptosis and glial scar formation to promote motor function recovery.

Novel multifunctional polyethylene glycol-transactivating-transduction protein-modified liposomes cross the blood-spinal cord barrier after spinal cord injury.

The blood-spinal cord barrier (BSCB) prevents many macromolecular agents from passing through to reach sites of injury in the spinal cord. This study evaluated the ability of a novel multifunctional liposome modified with polyethylene glycol (PEG) and transactivating-transduction protein (TAT) containing an iron core to cross the BSCB using a rat model of spinal cord injury. Rats were examined daily for a period of three days after spinal cord injury and injection of either the multifunctional modified liposome or control formulations using a 3.0 T magnetic resonance imaging spectrometer. A low signal was observed in the T2-weighted images. Prussian blue staining and flame atomic absorption spectrophotometry revealed that significantly more iron accumulated around the lesion site in the experimental group than the control groups (P < 0.05). The findings from this study suggest that this multifunctional liposome carrier can cross the BSCB to accumulate around the lesion site.

Regeneration of spinal cord with cell and gene therapy.

OBJECTIVE: Transplantation of fetal spinal cord cells (FSCC) can promote regeneration of injured spinal cord, while Schwann cells (SC) and some growth factors have a similar effect. However, the synergistic effects and optimal combination of these modalities have not yet been evaluated. In the current study, the efficiency of cell therapy of FSCC and/or SC, with/without growth factors (nerve growth factor [NGF] and brain-derived neurotrophic factor [BDNF]) was examined, with the aim of establishing an optimized protocol for spinal cord injury. METHODS: One hundred and twenty adult rats were randomly divided into six groups with 20 rats in each group. One week after the thoracic spinal cord injury model had been created, the rats were treated with different therapeutic modalities: Dulbecco's modified Eagles medium (DMEM) in Group I, FSCC in Group II, FSCC plus SC in Group III, FSCC plus SC over-expressing NGF in Group IV, FSCC plus SC over-expressing BDNF in Group V, and FSCC plus SC over-expressing both NGF and BDNF in Group VI. Subsequently, the rats were subjected to behavioral tests once a week after injury, while histology, immunohistochemistry and electron microscopy were performed at one and three month post-operation. RESULTS: Both SC and FSCC promoted regeneration of spinal cord injury when used separately, while a combination of the two types of cell resulted in better recovery than either alone. Both growth factors (NGF and BDNF) enhanced the outcomes of cell therapy, while synergistic effects meant that a combination of each individual component (group VI) achieved the best results according to locomotion scale, histology and immunoreactivity in the injured cords. CONCLUSION: SC, NGF and BDNF can enhance the outcome of FSCC therapy, while the combination of FSC with SC, NGF and BDNF is possibly the optimal protocol for clinical treatment of acute spinal cord injury.