Highly bioactive iridium metal-complex alleviates spinal cord injury via ROS scavenging and inflammation reduction.

Generation of a promising antioxidative reagent with superior biocompatibility is urgently needed to remedy spinal cord injuries (SCI), repair the damaged neurons and restrain the secondary injuries caused by inflammation-induced oxidative stress. Inhibitory elements in the injury sites and necessitous inherent neural regeneration ability were major challenges for functional recovery after spinal cord injuries. We here developed a highly bioactive iridium complex (IrFPHtz) with enhanced antioxidative activities and improved SCI therapeutic efficacy. Both in vivo and in vitro, IrFPHtz has exhibited neuroprotective and anti-inflammatory properties. Mechanically, IrFPHtz directly targets SOD1 and upregulates the expression of SOD1 to eliminate the excess Reactive Oxygen Species (ROS) production induced by SCI, and thus protecting neuron cells from further damage. As a result, IrFPHtz safeguarded the neurons and myelin sheaths against trauma, lessened glial scar conformations and facilitated the repair of neurons and long axon expansion in the glial scar. Furthermore, IrFPHtz significantly ameliorated the behavioral functions of SCI mice and promoted a satisfactory curative effect. Therefore, this study sheds light on a novel method for SCI treatment using IrFPHtz as a potential drug and implicates the clinical significance of metal complexes in diseases featuring with upregulated ROS species.

The effect of posterior lumbar dynamic fixation and intervertebral fusion on paraspinal muscles.

BACKGROUND: The aim of this study was to analyze the effect of unilateral K-rod dynamic internal fixation on paraspinal muscles for lumbar degenerative diseases. METHODS: This study retrospectively collected 52 patients who underwent lumbar surgery with the K-rod group or PLIF. The operation time, intraoperative blood loss, postoperative drainage volume, postoperative exercise time were compared in the two groups. The visual analog scale (VAS) score and the oswestry dysfunction index (ODI) were employed to evaluate the clinical outcomes. The functional cross-sectional area (FCSA) of the paraspinal muscles and paraspinal muscles fat infiltration were measured to assess on the paraspinal muscles. RESULTS: As compared with the PLIF group, the operation time, the postoperative time in the field, and the average postoperative hospital stay in the K-rod internal fixation group were significantly shortened. At the last follow-up, both the groups showed significant improvement in the VAS score and ODI. The FCSA atrophy of the upper and lower adjacent segments (UAS and LAS) of the K-rod internal group was significantly less than that of the PLIF group. The extent of increase in the fatty infiltration of the paraspinal muscles in the K-rod group was significantly lesser than that in the PLIF group. The postoperative low back pain of the two groups of patients was significantly positively correlated with the FCSA atrophy. CONCLUSIONS: As compared to PLIF, the posterior lumbar unilateral K-rod dynamic internal fixation showed significantly lesser paraspinal muscle atrophy and fatty infiltration, which were significantly positively correlated with postoperative low back pain.

Spastin interacts with collapsin response mediator protein 3 to regulate neurite growth and branching.

Cytoskeletal microtubule rearrangement and movement are crucial in the repair of spinal cord injury. Spastin plays an important role in the regulation of microtubule severing. Both spastin and collapsin response mediator proteins can regulate neurite growth and branching; however, whether spastin interacts with collapsin response mediator protein 3 (CRMP3) during this process remains unclear, as is the mechanism by which CRMP3 participates in the repair of spinal cord injury. In this study, we used a proteomics approach to identify key proteins associated with spinal cord injury repair. We then employed liquid chromatography-mass spectrometry to identify proteins that were able to interact with glutathione S-transferase-spastin. Then, co-immunoprecipitation and staining approaches were used to evaluate potential interactions between spastin and CRMP3. Finally, we co-transfected primary hippocampal neurons with CRMP3 and spastin to evaluate their role in neurite outgrowth. Mass spectrometry identified the role of CRMP3 in the spinal cord injury repair process. Liquid chromatography-mass spectrometry pulldown assays identified three CRMP3 peptides that were able to interact with spastin. CRMP3 and spastin were co-expressed in the spinal cord and were able to interact with one another in vitro and in vivo. Lastly, CRMP3 overexpression was able to enhance the ability of spastin to promote neurite growth and branching. Therefore, our results confirm that spastin and CRMP3 play roles in spinal cord injury repair by regulating neurite growth and branching. These proteins may therefore be novel targets for spinal cord injury repair. The Institutional Animal Care and Use Committee of Jinan University, China approved this study (approval No. IACUS-20181008-03) on October 8, 2018.

SUMOylation of spastin promotes the internalization of GluA1 and regulates dendritic spine morphology by targeting microtubule dynamics.

Dendritic spines are specialized structures involved in neuronal processes on which excitatory synaptic contact occurs. The microtubule cytoskeleton is vital for maintaining spine morphology and mature synapses. Spastin is related to microtubule-severing proteases and is involved in synaptic bouton formation. However, it is not yet known if spastin can be modified by Small Ubiquitin-like Modifier (SUMO) or how this modification regulates dendritic spines. Spastin was shown to be SUMOylated at K427, and its deSUMOylation promoted microtubule stability. In addition, SUMOylation of spastin was shown to affect signalling pathways associated with long term synaptic depression. SUMOylated spastin promoted the development of dendrites and dendritic spines. Moreover, SUMOylated spastin regulated endocytosis and affected the transport of the AMPA receptor, GluA1. Our findings suggest that SUMOylation of spastin promotes GluA1 internalization and regulates dendritic spine morphology through targeting of microtubule dynamics.

Analysis of clinical effect and radiographic outcomes of Isobar TTL system for two-segment lumbar degenerative disease: a retrospective study.

BACKGROUND: Nonfusion fixation is an effective way to treat lumbar degeneration. In the present study, we analyzed the clinical effects and radiographic outcomes of the Isobar TTL system used to treat two-segment lumbar degenerative disease. METHOD: Forty-one patients diagnosed with two-segment lumbar degenerative disease underwent surgical implantation of the Isobar TTL dynamic stabilization system (n = 20) or a rigid system (n = 21) from January 2013 to June 2017. The mean follow-up time was 23.6 (range 15-37) months. Clinical results were evaluated with the Oswestry Disability Index (ODI), modified Macnab criteria, and the visual analog score (VAS). Radiographic evaluations included the height of the intervertebral space and the range of motion (ROM) of the treated and adjacent segments. The intervertebral disc signal was classified using the modified Pfirrmann grading system and the University of California at Los Angeles (UCLA) system. RESULTS: The clinical results, including the ODI and VAS, showed that there was significant improvement in the two groups after implantation and that the difference between the two groups was not significant. In addition, the clinical efficacy indicated by the modified Macnab criteria for the two groups was similar. Radiological outcomes included the height of the intervertebral space, lumbar mobility, and intervertebral disc signal. The height of the intervertebral space of the upper adjacent segment L2/3 in the rigid group was significantly lower than that in the Isobar TTL group at the last follow-up. Furthermore, the number of ROMs of the fixed-segment L3/4 in the Isobar TTL group was significantly less than that before implantation, suggesting that the fixed-segment ROMs in the Isobar TTL group were limited. In addition, the ROM of the upper adjacent segment L2/3 in the last follow-up of the rigid group increased significantly, while that of the Isobar TTL group did not change after implantation. Finally, the incidence of adjacent-segment degeneration (ASD) was significantly greater in the rigid group than in the Isobar TTL group according to the UCLA system. CONCLUSION: The Isobar TTL system can be clinically effective for treating two-segment lumbar degenerative disease. Compared with rigid fixation, the Isobar TTL system yielded better radiographic outcomes and maintained the mobility of the treated segments with less impact on the proximal adjacent segment.

Effect of methylprednisolone on the activities of caspase-3, -6, -8 and -9 in rabbits with acute spinal cord injury.

The present study aimed to investigate the effect of methylprednisolone (MP) on the activities of caspase-3, -6, -8 and -9 in rabbits with acute spinal cord injury (ASCI) and to explore the mechanism underlying the antiapoptotic effect of MP on ASCI. Modified Allen's method was employed to establish the ASCI animal model. The animals were randomly divided into a sham (S; n=12), ASCI (C; n=36) and MP group (T; n=36). At 8, 24 and 72 h and 7, 14 and 28 days after ASCI, the animals were sacrificed and the spinal cord was collected. The absorbance (A) was measured with a microplate reader and the activities of caspase-3, -6, -8 and -9 were calculated followed by comparisons among the groups. In the S group, the activities of the four caspases were low. In the C and T groups, the caspase activities increased at 8 h after injury, peaked at 24 h and remained at a high level 3 days after injury. However, the caspase activities began to decrease at 7 days after injury and were significantly reduced at 14 and 28 days after ASCI. Furthermore, the caspase activities in the T group were markedly lower than those in the C group at 8 and 24 h and 3 and 7 days after surgery (P<0.05), but significant differences were not observed at 14 and 28 days after injury (P>0.05). In conclusion, MP exerted an antiapoptotic effect via inhibition of the activities of caspase-3, -6, -8 and -9 in an animal model of ASCI.