Investigation of efficacy of treatment in spinal cord injury: Erythropoietin versus methylprednisolone

Recombinant human erythropoietin plus methylprednisolone versus methylprednisolone in treatment of acute spinal cord injury：protocol for a systematic review and meta-analysis

INTRODUCTION

Recent studies in animal models indicate that recombinant human erythropoietin (rHuEPO) is very effective in enhancing neurological recovery after spinal cord injury (SCI). We described a protocol aimed at evaluating the efficacy of rHuEPO plus methylprednisolone (MP) compared with MP alone in improving neurological function of patients with SCI in randomised controlled trials (RCTs).

METHODS AND ANALYSIS

This study aims to explore the effect of rHuEPO combined with MP on neurological function in patients with SCI through a meta-analysis. To this end, the authors will search eight research databases for data retrieval: MEDLINE, China National Knowledge Infrastructure, Wan Fang, China Biology Medicine dis, Web of Science, PubMed, Cochrane and Embase for RCTs on SCI in any language. The primary outcome will be the American Spinal Injury Association score at the time of follow-up. The secondary outcomes will be the WHOQOL-100 instrument score, neurophysiological state and related factors. Two authors will independently search literature records, scan titles, abstracts and full texts, collect data, and assess materials for risk of bias. Stata V.14.0 will be used for statistical analysis.

ETHICS AND DISSEMINATION

This research is exempt from ethics approval because the work is carried out on published documents. We will disseminate this protocol in scientific conferences and a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021260688.

Neurological recovery and antioxidant effect of erythropoietin for spinal cord injury: A systematic review and meta-analysis

Background

To critically evaluate the neurological recovery effects and antioxidant effects of erythropoietin (EPO) in rat models of spinal cord injury (SCI).

Methods

The PubMed, EMBASE, MEDLINE, ScienceDirect, and Web of Science were searched for animal experiments applying EPO to treat SCI to January 2022. We included studies which examined neurological function by the Basso, Beattie, and Bresnahan (BBB) scale, as well as cavity area and spared area, and determining the molecular-biological analysis of antioxidative effects by malondialdehyde (MDA) levels in spinal cord tissues. Meta-analysis were performed with Review Manager 5.4 software.

Results

A total of 33 studies were included in this review. The results of the meta-analysis showed that SCI rats receiving EPO therapy showed a significant locomotor function recovery after 14 days compared with control, then the superiority of EPO therapy maintained to 28 days from BBB scale. Compared with the control group, the cavity area was reduced [4 studies, weighted mean difference (WMD) = −16.65, 95% CI (−30.74 to −2.55), P = 0.02] and spared area was increased [3 studies, WMD =11.53, 95% CI (1.34 to 21.72), P = 0.03] by EPO. Meanwhile, MDA levels [2 studies, WMD = −0.63 (−1.09 to −0.18), P = 0.007] were improved in the EPO treatment group compared with control, which indicated its antioxidant effect. The subgroup analysis recommended 5,000 UI/kg is the most effective dose [WMD = 4.05 (2.23, 5.88), P < 0.0001], although its effect was not statistically different from that of 1,000 UI/kg. Meanwhile, the different rat strains (Sprague-Dawley vs. Wistar), and models of animals, as well as administration method (single or multiple administration) of EPO did not affect the neuroprotective effect of EPO for SCI.

Conclusions

This systematic review indicated that EPO can promote the recovery of the locomotor function of SCI rats. The mechanism exploration of EPO needs to be verified by experiments, and then carefully designed randomized controlled trials are needed to explore its neural recovery effects.

Perspectives in the Cell-Based Therapies of Various Aspects of the Spinal Cord Injury-Associated Pathologies: Lessons from the Animal Models

Traumatic injury of the spinal cord (SCI) is a devastating neurological condition often leading to severe dysfunctions, therefore an improvement in clinical treatment for SCI patients is urgently needed. The potential benefits of transplantation of various cell types into the injured spinal cord have been intensively investigated in preclinical SCI models and clinical trials. Despite the many challenges that are still ahead, cell transplantation alone or in combination with other factors, such as artificial matrices, seems to be the most promising perspective. Here, we reviewed recent advances in cell-based experimental strategies supporting or restoring the function of the injured spinal cord with a particular focus on the regenerative mechanisms that could define their clinical translation.

Facile fabrication of an erythropoietin-alginate/chitosan hydrogel and evaluation of its local therapeutic effects on spinal cord injury in rats

BACKGROUND AND OBJECTIVE

Spinal cord injury (SCI) is a major disabling disorder for which no effective treatment has yet been found. Regenerative incapability of neuronal cells as well as the secondary mechanisms of injury are the major reasons behind this clinical frustration. Thus, here we fabricated an erythropoietin-chitosan/alginate (EPO-CH/AL) hydrogel and investigated its local therapeutic effects on the apoptotic and inflammatory indices of SCI secondary injury.

METHODS

EPO-CH/AL hydrogels were fabricated by the ionic gelation method, and they were characterized using SEM and FTIR. In vitro drug release profile of EPO-CH/AL hydrogels was evaluated by UV-vis spectroscopy. Experimental SCI was inflicted in rats which were then treated with CH/AL hydrogels containing different doses of EPO (1000, 5000 and 10,000 IU/kg). The relative expression of Bax and Bcl2 (apoptosis index) and active and inactive forms of NF-κB (inflammation index) were assessed using western blot. Total serum levels of TNF-α were also assessed with ELISA, and histopathological and immunohistochemistry studies were carried out to check the overall changes in the injured tissues.

RESULTS

In vitro drug release test indicated that the EPO-CH/AL hydrogels had a sustained- and controlled-release profile for EPO under these conditions. All the fabricated hydrogels dramatically reduced the elevated inflammation and apoptosis indices of the SCI-inflicted rats (p ≤ 0.05). Nevertheless, only EPO-CH/AL hydrogel (1000 IU/kg EPO) significantly improved the tissue repair and histopathological appearance of the spinal cord at the sites of injury.

CONCLUSION

Based on our findings, EPO-CH/AL hydrogel (1000 IU/kg EPO) can effectively improve experimental SCI in rats via inhibiting apoptosis and inflammation. Further studies are warranted to elucidate the contributing role of the scaffold in the observed effects.

Standardization of an experimental model of intradural injection after spinal cord injury in rats

OBJECTIVES

The intrathecal route has not yet been thoroughly standardized and evaluated in an experimental model of spinal cord injury (SCI) in Wistar rats. The objective of this study was to standardize and evaluate the effect of intradural injection in this animal model.

METHOD

The animals were divided into 6 groups: 1) laminectomy and intradural catheter; 2) laminectomy, intradural catheter and infusion; 3) only SCI; 4) SCI and intradural catheter; 5) SCI, intradural catheter and infusion; and 6) control (laminectomy only). Motor evaluations were performed using the Basso, Beattie and Bresnahan (BBB) scale and the horizontal ladder test; motor evoked potentials were measured for functional evaluation, and histological evaluation was performed as well. All experimental data underwent statistical analysis.

RESULTS

Regarding motor evoked potentials, the groups with experimental SCI had worse results than those without, but neither dural puncture nor the injection of intrathecal solution aggravated the effects of isolated SCI. Regarding histology, adverse tissue effects were observed in animals with SCI. On average, the BBB scores had the same statistical behaviour as the horizontal ladder results, and at every evaluated timepoint, the groups without SCI presented scored significantly better than those with SCI (p<0.05). The difference in performance on motor tests between rats with and without experimental SCI persisted from the first to the last test.

CONCLUSIONS

The present work standardizes the model of intradural injection in experimental SCI in rats. Intrathecal puncture and injection did not independently cause significant functional or histological changes.

Human Brain-Derived Neurotrophic Factor Gene-Modified Bone Marrow Mesenchymal Stem Cells Combined With Erythropoietin Can Improve Acute Spinal Cord Injury

Objective:

To assess the effect as well as mechanism of bone marrow mesenchymal stem cells (BMSCs) modified by the human brain–derived neurotrophic factor gene combined with erythropoietin (EPO) in the treatment of acute spinal cord injury (SCI) in rats.

Methods:

The Brain-derived neurotrophic factor (BDNF) gene was transected by a virus vector. Rats with SCI were randomly split into following groups: The normal saline (NS) group, the EPO group, The Basso, Beattie, and Bresnahan scores, messenger RNA BDNF expression, and apoptosis rates were compared between the 4 groups at 1, 3, 7, 14, and 21 days after SCI.

Results:

At 7, 14, and 21 days after operation, the expression of the BDNF gene in the other 3 groups was higher than that of the NS group, and the difference was statistically significant (P < .05). The apoptosis rate in the combined group was less than that of NS, EPO, and BDNF/BMSC groups, and the differences were statistically significant (P < .05).

Conclusion:

Brain-derived neurotrophic factor gene-modified BMSC transplantation combined with EPO can promote the repair of nerve function after SCI in rats.

Combination Therapy With Hyperbaric Oxygen and Erythropoietin Inhibits Neuronal Apoptosis and Improves Recovery in Rats With Spinal Cord Injury

BACKGROUND

Apoptosis plays an important role in various diseases, including spinal cord injury (SCI). Hyperbaric oxygen (HBO) and erythropoietin (EPO) promote the recovery from SCI, but the relationship between apoptosis and the combination therapeutic effect is not completely clear.

OBJECTIVE

The purpose of this study was to investigate the effects of HBO and EPO on SCI and the mechanisms that underlie their therapeutic benefits.

DESIGN

The study was designed to explore the effects of HBO and EPO on SCI through a randomized controlled trial.

METHODS

Sixty young developing female Sprague-Dawley rats were randomly divided into groups of 12 rats receiving sham, SCI, HBO, EPO, or HBO plus EPO. The SCI model was modified with the Allen method to better control consistency. HBO was performed for 1 hour per day for a total of 21 days, and EPO was given once per week for a total of 3 weeks. Both methods were performed 2 hours after SCI. Locomotor function was evaluated with the 21-point Basso-Beattie-Bresnahan Locomotor Rating Scale, an inclined-plane test, and a footprint analysis. All genes were detected by Western blotting and immunohistochemistry. The level of cell apoptosis was determined by Hoechst staining.

RESULTS

The results showed that HBO and EPO promoted the recovery of locomotor function in the hind limbs of rats by inhibiting the apoptosis of neurons. During this period, the expression of B-cell lymphoma/leukemia 2 protein (Bcl-2) increased significantly, whereas the expression of Bcl-2-associated X protein (Bax) and cleaved caspase 3 decreased significantly, indicating the inhibition of apoptosis. Meanwhile, the expression of G protein-coupled receptor 17 decreased, and that of myelin basic protein increased, suggesting that there may be a potential connection between demyelination and neuronal apoptosis.

LIMITATIONS

The limitations of the study include deviations in the preparation of SCI models; lack of reverse validation of molecular mechanisms; absence of in vitro cell experiments; and only one time point after SCI was studied.

CONCLUSIONS

HBO and EPO treatments are beneficial for SCI, especially when the 2 therapies are combined.