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The central nervous system's limited capacity for regeneration often leads to permanent neuronal loss following injury. Reprogramming resident reactive astrocytes into induced neurons at the site of injury is a promising strategy for neural repair, but challenges persist in stabilizing and accurately targeting viral vectors for transgene expression. In this study, we employed a bioinspired self-assembling peptide (SAP) hydrogel for the precise and controlled release of a hybrid adeno-associated virus (AAV) vector, AAVDJ, carrying the NeuroD1 neural reprogramming transgene. This method effectively mitigates the issues of high viral dosage at the target site, off-target delivery, and immunogenic reactions, enhancing the vector's targeting and reprogramming efficiency. In vitro, this vector successfully induced neuron formation, as confirmed by morphological, histochemical, and electrophysiological analyses. In vivo, SAP-mediated delivery of AAVDJ-NeuroD1 facilitated the trans-differentiation of reactive host astrocytes into induced neurons, concurrently reducing glial scarring. Our findings introduce a safe and effective method for treating central nervous system injuries, marking a significant advancement in regenerative neuroscience.

Current therapies for the devastating damage caused by traumatic brain injuries (TBI) are limited. This is in part due to poor drug efficacy to modulate neuroinflammation, angiogenesis and/or promoting neuroprotection and is the combined result of challenges in getting drugs across the blood brain barrier, in a targeted approach. The negative impact of the injured extracellular matrix (ECM) has been identified as a factor in restricting post-injury plasticity of residual neurons and is shown to reduce the functional integration of grafted cells. Therefore, new strategies are needed to manipulate the extracellular environment at the subacute phase to enhance brain regeneration. In this review, potential strategies are to be discussed for the treatment of TBI by using self-assembling peptide (SAP) hydrogels, fabricated via the rational design of supramolecular peptide scaffolds, as an artificial ECM which under the appropriate conditions yields a supramolecular hydrogel. Sequence selection of the peptides allows the tuning of these hydrogels' physical and biochemical properties such as charge, hydrophobicity, cell adhesiveness, stiffness, factor presentation, degradation profile and responsiveness to (external) stimuli. This review aims to facilitate the development of more intelligent biomaterials in the future to satisfy the parameters, requirements, and opportunities for the effective treatment of TBI.

AIM: To systematically identify and evaluate the measurement properties of patient-reported outcome measures (PROMs) and observer-reported outcome measures (parent proxy report) of pain coping tools that have been used with children and young adults (aged 0-24 years) with a neurodevelopmental disability. METHOD: A two-stage search using MEDLINE, Embase, CINAHL, Web of Science, and PsycInfo was conducted. Search 1 in August 2021 identified pain coping tools used in neurodevelopmental disability and search 2 in September 2021 located additional studies evaluating the measurement properties of these tools. Methodological quality was assessed using the COnsensus-based Standards for the Selection of Health Measurement INstruments (COSMIN) guidelines (PROSPERO protocol registration no. CRD42021273031). RESULTS: Sixteen studies identified seven pain coping tools, all PROMs and observer-reported outcome measures (parent proxy report) versions. The measurement properties of the seven tools were appraised in 44 studies. No tool had high-quality evidence for any measurement property or evidence for all nine measurement properties as outlined by COSMIN. Only one tool had content validity for individuals with neurodevelopmental disability: the Cerebral Palsy Quality of Life tool. INTERPRETATION: Pain coping assessment tools with self-report and parent proxy versions are available; however, measurement invariance has not been tested in young adults with a neurodevelopmental disability. This is an area for future research.

AIM: To determine whether a task-specific physiotherapist-led training approach is more effective than a non-specific parent-led home programme for attaining bicycle-riding goals in ambulant children with cerebral palsy (CP). METHOD: Sixty-two ambulant children with CP aged 6 to 15 years (33 males, 29 females, mean age 9y 6mo) with bicycle-riding goals participated in this multi-centre, assessor-blind, parallel-group, superiority randomized controlled trial. Children in the task-specific group participated in a physiotherapist-led, group-based, intensive training programme. Children in the parent-led home group were provided with a practice schedule, generic written information, and telephone support. Both programmes involved a 1-week training period. The primary outcome was goal attainment at 1 week after training measured using the Goal Attainment Scale. Secondary outcomes included bicycle skills, participation in bicycle riding, functional skills, self-perception, physical activity, and health-related quality of life at 1 week and 3 months after training. RESULTS: Children in the task-specific training group had greater odds of goal attainment than those in the parent-led home programme at 1 week after intervention (odds ratio [OR] 10.4, 95% confidence interval [CI] 2.8-38.6), with evidence for superiority retained at 3 months (OR 4.0, 95% CI 1.3-12.5). INTERPRETATION: The task-specific physiotherapist-led training approach was more effective for attaining bicycle-riding goals than a non-specific parent-led home programme in ambulant children with CP.

Gene delivery has been extensively investigated for introducing foreign genetic material into cells to promote expression of therapeutic proteins or to silence relevant genes. This approach can regulate genetic or epigenetic disorders, offering an attractive alternative to pharmacological therapy or invasive protein delivery options. However, the exciting potential of viral gene therapy has yet to be fully realized, with a number of clinical trials failing to deliver optimal therapeutic outcomes. Reasons for this include difficulty in achieving localized delivery, and subsequently lower efficacy at the target site, as well as poor or inconsistent transduction efficiency. Thus, ongoing efforts are focused on improving local viral delivery and enhancing its efficiency. Recently, biomaterials have been exploited as an option for more controlled, targeted and programmable gene delivery. There is a growing body of literature demonstrating the efficacy of biomaterials and their potential advantages over other delivery strategies. This review explores current limitations of gene delivery and the progress of biomaterial-mediated gene delivery. The combination of biomaterials and gene vectors holds the potential to surmount major challenges, including the uncontrolled release of viral vectors with random delivery duration, poorly localized viral delivery with associated off-target effects, limited viral tropism, and immune safety concerns.

AIM: To evaluate pain prevalence and characteristics in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) cerebral palsy (CP) motor types. METHOD: Seventy-five participants with a diagnosis of CP and confirmed dyskinetic or mixed (dyskinetic/spastic) motor type took part in a multisite cross-sectional study. The primary outcome was carer-reported pain prevalence (preceding 2wks) measured using the Health Utilities Index-3. Secondary outcomes were chronicity, intensity, body locations, quality of life, and activity impact. RESULTS: Mean participant age was 10 years 11 months (SD 4y 2mo, range 5-18y). There were 44 males and 31 females and 37 (49%) had predominant dyskinetic CP. Pain was prevalent in 85% and it was chronic in 77% of participants. Fifty-two per cent experienced moderate-to-high carer-reported pain intensity, which was significantly associated with predominant dyskinetic motor types (p=0.008). Pain occurred at multiple body locations (5 out of 21), with significantly increased numbers of locations at higher Gross Motor Function Classification System levels (p=0.02). Face, jaw, and temple pain was significantly associated with predominant dyskinetic motor types (p=0.005). Poorer carer proxy-reported quality of life was detected in those with chronic pain compared to those without (p=0.03); however, chronic pain did not affect quality of life for self-reporting participants. INTERPRETATION: Pain was highly prevalent in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) motor types, highlighting a population in need of lifespan pain management. WHAT THIS PAPER ADDS: Chronic pain prevalence in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) motor types is high. Pain occurs across multiple body locations in predominant dyskinetic and mixed (dyskinetic/spastic) motor types. Less recognized locations of pain include the face, jaw, and temple for predominant d

BACKGROUND: To explore the lived experience of chronic pain and dyskinesia in children and adolescents with cerebral palsy. METHODS: A convergent parallel mixed methods design was undertaken. First, a quantitative cross-sectional study of participants able to self-report their quality of life was undertaken. This study characterised pain chronicity, intensity, body locations, and quality of life. Second, semi-structured interviews were undertaken with a subset of children and adolescents experiencing chronic pain. RESULTS: Twenty-five children and adolescents took part in the cross-sectional study, 23 of whom experienced chronic pain and 13 of moderate intensity. Pain was often located in multiple bodily regions (6/21), with no trends in quality of life outcomes detected. Eight participated in semi-structured interviews, which identified three key themes including 'lives embedded with dyskinesia', 'real world challenges of chronic pain', and 'still learning strategies to manage their pain and dyskinesia'. CONCLUSIONS: A high proportion of children and adolescents with cerebral palsy and dyskinesia who were able to self-report experienced chronic pain. The physical and emotional impacts of living with chronic pain and dyskinesia existed along a spectrum, from those with lesser to greater extent of their impacts. Children and adolescents may benefit from targeted chronic pain education and management within bio-psychosocial models.

AIM: The primary aim of this review is to evaluate the evidence for pain prevalence in children and young adults with cerebral palsy. Secondary aims are to identify pain characteristics and types of pain measurement used in this population. METHOD: Ovid MEDLINE, Embase, CINAHL Plus, and PubMed were searched in October 2016 and updated in November 2017. Two authors independently screened studies according to Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Pain outcomes were categorized within a biopsychosocial pain framework, with pain prevalence extracted for all recall periods and measurement types. RESULTS: One hundred and six publications from 57 studies met inclusion criteria. Pain prevalence varied widely from 14 per cent to 76 per cent and was higher in females, older age groups, and those classified within Gross Motor Function Classification System level V. Pain was most frequent in the lower limbs, back, and abdomen and associated with reduced quality of life or health status. The influence of pain on psychological functioning, interference, and participation was inconclusive. INTERPRETATION: Variation exists in reported pain prevalence because of sampling bias, inconsistent measurement, varying recall periods, and use of different participant age ranges. WHAT THIS PAPER ADDS: Pain prevalence varies from 14 per cent to 76 per cent in children and young adults with cerebral palsy. Pain is more prevalent in females, older age groups, and children in Gross Motor Function Classification System level V.

INTRODUCTION: Two-wheel bike riding can be a goal for children with cerebral palsy (CP) and a means of participating in physical activity. It is possible for some children with CP to ride a two-wheel bike; however, currently far fewer can ride compared with their typically developing peers. Evidence supports training targeted towards goals of the child with CP and their family; yet there is little evidence to guide best-practice bike skills training. Task-specific training may lead to attainment of two-wheel bike-specific goals. This study aims to determine if a novel task-specific approach to training two-wheel bike skills is more effective than a parent-led home programme for attaining individualised two-wheel bike-specific goals in independently ambulant children with CP aged 6-15 years. METHODS AND ANALYSIS: Sixty eligible children with CP (Gross Motor Function Classification System levels I-II) aged 6-15 years with goals relating to riding a two-wheel bike will be randomised to either a novel task-specific centre-based group programme (intervention) or a parent-led home-based programme (comparison), both involving a 1-week intervention period. The primary outcome is goal attainment in the week following the intervention period (T1). Secondary outcomes include: goal attainment and participation in physical activity at 3 months postintervention (T2) and bike skills, attendance and involvement in bike riding, self-perception and functional skills at T1 and T2. Economic appraisal will involve cost-effectiveness and cost-utility analyses. Adherence of clinicians and parents to the intervention and comparison protocols will be assessed. Linear and logistic regression will be used to assess the effect of the intervention, adjusted for site as used in the randomisation process. ETHICS AND DISSEMINATION: This study was approved by the Human Research and Ethics Committees at The Royal Children's Hospital (#36209). Results will be disseminated via peer-reviewed publicatio

AIM: Limited information exists on the ability of children with cerebral palsy (CP) to ride a two-wheel bicycle, an activity that may improve health and participation. We aimed to describe bicycle-riding ability and variables associated with ability to ride in children with CP (Gross Motor Functional Classification System [GMFCS] levels I-II) compared with children with typical development. METHOD: This case-control study surveyed parents of 114 children with CP and 87 children with typical development aged 6 to 15 years (115 males, mean age 9y 11mo, standard deviation [SD] 2y 10mo). Kaplan-Meier methods were used to compare proportions able to ride at any given age between the two groups. Logistic regression was used to assess variables associated with ability to ride for children with CP and typical development separately. RESULTS: The proportion of children with CP able to ride at each level of bicycle-riding ability was substantially lower at each age than peers with typical development (p<0.001). While most children with typical development were able to ride independently by 10 years of age, 51% of children with CP classified as GMFCS level I and 3% of those classified as GMFCS level II had obtained independent riding in the community by 15 years of age. Variables associated with ability to ride for children classified as GMFCS level I were age and parent-rated importance of their child being able to ride. INTERPRETATION: Some independently ambulant children with CP can learn to ride a bicycle, in particular if they are classified as GMFCS level I. Variables associated with ability to ride deserve consideration in shaping future efforts for the majority of this population who are not yet able to ride.

OBJECTIVES: The primary objective is to systematically evaluate the evidence for the effectiveness of task-specific training (TST) of gross motor skills for improving activity and/or participation outcomes in ambulant school-aged children with cerebral palsy (CP). The secondary objective is to identify motor learning strategies reported within TST and assess relationship to outcome. DESIGN: Systematic review. METHOD: Relevant databases were searched for studies including: children with CP (mean age >4 years and >60% of the sample ambulant); TST targeting gross motor skills and activity (skill performance, gross motor function and functional skills) and/or participation-related outcomes. Quality of included studies was assessed using standardised tools for risk of bias, study design and quality of evidence across outcomes. Continuous data were summarised for each study using standardised mean difference (SMD) and 95% CIs. RESULTS: Thirteen studies met inclusion criteria: eight randomised controlled trials (RCTs), three comparative studies, one repeated-measures study and one single-subject design study. Risk of bias was moderate across studies. Components of TST varied and were often poorly reported. Within-group effects of TST were positive across all outcomes of interest in 11 studies. In RCTs, between-group effects were conflicting for skill performance and functional skills, positive for participation-related outcomes (one study: Life-HABITS performance SMD=1.19, 95% CI 0.3 to 2.07, p<0.001; Life-HABITS satisfaction SMD=1.29, 95% CI 0.40 to 2.18, p=0.001), while no difference or negative effects were found for gross motor function. The quality of evidence was low-to-moderate overall. Variability and poor reporting of motor learning strategies limited assessment of relationship to outcome. CONCLUSIONS: Limited evidence for TST for gross motor skills in ambulant children with CP exists for improving activity and participation-related outcomes and recommendations fo

© 2017 Li et al. Large numbers of long noncoding RNAs have been discovered in recent years, but only a few have been characterized. NEAT1 (nuclear paraspeckle assembly transcript 1) is a mammalian long noncoding RNA that is important for the reproductive physiology of mice, cancer development, and the formation of subnuclear bodies termed paraspeckles. The two major isoforms of NEAT1 (3.7 kb NEAT1-1 and 23 kb NEAT1-2 in human) are generated from a common promoter and are produced through the use of alternative transcription termination sites. This gene structure has made the functional relationship between the two isoforms difficult to dissect. Here we used CRISPR-Cas9 genome editing to create several different cell lines: total NEAT1 knockout cells, cells that only express the short form NEAT1-1, and cells with twofold more NEAT1-2. Using these reagents, we obtained evidence that NEAT1-1 is not a major component of paraspeckles. In addition, our data suggest NEAT1-1 localizes in numerous nonparaspeckle foci we termed "microspeckles," which may carry paraspeckle-independent functions. This study highlights the complexity of lncRNA and showcases how genome editing tools are useful in dissecting the structural and functional roles of overlapping transcripts.

© 2017 The Author(s). Background: Following partial injury to the central nervous system, cells beyond the initial injury site undergo secondary degeneration, exacerbating loss of neurons, compact myelin and function. Changes in Ca2+ flux are associated with metabolic and structural changes, but it is not yet clear how flux through specific ion channels contributes to the various pathologies. Here, partial optic nerve transection in adult female rats was used to model secondary degeneration. Treatment with combinations of three ion channel inhibitors was used as a tool to investigate which elements of oxidative and structural damage related to long term functional outcomes. The inhibitors employed were the voltage gated Ca2+ channel inhibitor Lomerizine (Lom), the Ca2+ permeable AMPA receptor inhibitor YM872 and the P2X7 receptor inhibitor oxATP. Results: Following partial optic nerve transection, hyper-phosphorylation of Tau and acetylated tubulin immunoreactivity were increased, and Nogo-A immunoreactivity was decreased, indicating that axonal changes occurred acutely. All combinations of ion channel inhibitors reduced hyper-phosphorylation of Tau and increased Nogo-A immunoreactivity at day 3 after injury. However, only Lom/oxATP or all three inhibitors in combination significantly reduced acetylated tubulin immunoreactivity. Most combinations of ion channel inhibitors were effective in restoring the lengths of the paranode and the paranodal gap, indicative of the length of the node of Ranvier, following injury. However, only all three inhibitors in combination restored to normal Ankyrin G length at the node of Ranvier. Similarly, HNE immunoreactivity and loss of oligodendrocyte precursor cells were only limited by treatment with all three ion channel inhibitors in combination. Conclusions: Data indicate that inhibiting any of a range of ion channels preserves certain elements of axon and node structure and limits some oxidative damage following injury, whereas i

Spiral ganglion neurons (SGNs), the target cells of the cochlear implant, undergo gradual degeneration following loss of the sensory epithelium in deafness. The preservation of a viable population of SGNs in deafness can be achieved in animal models with exogenous application of neurotrophins such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3. For translation into clinical application, a suitable delivery strategy that provides ongoing neurotrophic support and promotes long-term SGN survival is required. Cell-based neurotrophin treatment has the potential to meet the specific requirements for clinical application, and we have previously reported that Schwann cells genetically modified to express BDNF can support SGN survival in deafness for 4 weeks. This study aimed to investigate various parameters important for the development of a long-term cell-based neurotrophin treatment to support SGN survival. Specifically, we investigated different (i) cell types, (ii) gene transfer methods and (iii) neurotrophins, in order to determine which variables may provide long-term neurotrophin expression and which, therefore, may be the most effective for supporting long-term SGN survival in vivo. We found that fibroblasts that were nucleofected to express BDNF provided the most sustained neurotrophin expression, with ongoing BDNF expression for at least 30 weeks. In addition, the secreted neurotrophin was biologically active and elicited survival effects on SGNs in vitro. Nucleofected fibroblasts may therefore represent a method for safe, long-term delivery of neurotrophins to the deafened cochlea to support SGN survival in deafness.

Secondary degeneration of nerve tissue adjacent to a traumatic injury results in further loss of neurons, glia and function, via mechanisms that may involve oxidative stress. However, changes in indicators of oxidative stress have not yet been demonstrated in oligodendrocytes vulnerable to secondary degeneration in vivo. We show increases in the oxidative stress indicator carboxymethyl lysine at days 1 and 3 after injury in oligodendrocytes vulnerable to secondary degeneration. Dihydroethidium staining for superoxide is reduced, indicating endogenous control of this particular reactive species after injury. Concurrently, node of Ranvier/paranode complexes are altered, with significant lengthening of the paranodal gap and paranode as well as paranode disorganisation. Therapeutic administration of 670 nm light is thought to improve oxidative metabolism via mechanisms that may include increased activity of cytochrome c oxidase. Here, we show that light at 670 nm, delivered for 30 minutes per day, results in in vivo increases in cytochrome c oxidase activity co-localised with oligodendrocytes. Short term (1 day) 670 nm light treatment is associated with reductions in reactive species at the injury site. In optic nerve vulnerable to secondary degeneration superoxide in oligodendrocytes is reduced relative to handling controls, and is associated with reduced paranode abnormalities. Long term (3 month) administration of 670 nm light preserves retinal ganglion cells vulnerable to secondary degeneration and maintains visual function, as assessed by the optokinetic nystagmus visual reflex. Light at a wavelength of 670 nm may serve as a therapeutic intervention for treatment of secondary degeneration following neurotrauma.

Partial injury to the central nervous system (CNS) is exacerbated by additional loss of neurons and glia via toxic events known as secondary degeneration. Using partial transection of the rat optic nerve (ON) as a model, we have previously shown that myelin decompaction persists during secondary degeneration. Failure to repair myelin abnormalities during secondary degeneration may be attributed to insufficient OPC proliferation and/or differentiation to compensate for loss of oligodendrocyte lineage cells (oligodendroglia). Following partial ON transection, we found that sub-populations of oligodendroglia and other olig2+ glia were differentially influenced by injury. A high proportion of NG2+/olig2-, NG2+/olig2+ and CC1-/olig2+ cells proliferated (Ki67+) at 3 days, prior to the onset of death (TUNEL+) at 7 days, suggesting injury-related cues triggered proliferation rather than early loss of oligodendroglia. Despite this, a high proportion (20%) of the NG2+/olig2+ OPCs were TUNEL+ at 3 months, and numbers remained chronically lower, indicating that proliferation of these cells was insufficient to maintain population numbers. There was significant death of NG2+/olig2- and NG2-/olig2+ cells at 7 days, however population densities remained stable, suggesting proliferation was sufficient to sustain cell numbers. Relatively few TUNEL+/CC1+ cells were detected at 7 days, and no change in density indicated that mature CC1+ oligodendrocytes were resistant to secondary degeneration in vivo. Mature CC1+/olig2- oligodendrocyte density increased at 3 days, reflecting early oligogenesis, while the appearance of shortened myelin internodes at 3 months suggested remyelination. Taken together, chronic OPC decreases may contribute to the persistent myelin abnormalities and functional loss seen in ON during secondary degeneration.

PURPOSE: To examine chronic changes occurring at 6 months following partial optic nerve (ON) transection, assessing optic axons, myelin, and visual function. METHODS: Dorsal ON axons were transected, leaving ventral optic axons vulnerable to secondary degeneration. At 3 and 6 months following partial transection, toluidine-blue stained sections were used to assess dimensions of the ON injury site. Transmission electron microscopy (TEM) images of ventral ON were used to quantify numbers, diameter, area, and myelin thickness of optic axons. Immunohistochemistry and fluoromyelin staining were used to assess semiquantitatively myelin protein, lipids in ventral ON, and retinal ganglion cells (RGCs) in midventral retina. Visuomotor function was assessed using optokinetic nystagmus. RESULTS: Following partial ON transection, optic axons and function remained disrupted at 6 months. Although ventral ON swelling observed at 3 months (P ≤ 0.05) receded to normal by 6 months, ultrastructurally, myelinated axons remained swollen (P ≥ 0.05), and myelin thickness increased (P ≤ 0.05) due to loosening of lamellae and an increase in the number of intraperiodic lines. Axons with decompacted myelin persisted and were distinguished as having large axonal calibers and thicker myelin sheaths. Nevertheless, progressive loss of myelin lipid staining with fluoromyelin was seen at 6 months. Despite no further loss of ventral optic axons between 3 and 6 months (P ≥ 0.05), visuomotor function progressively declined at 6 months following partial transection (P ≤ 0.05). CONCLUSIONS: Continued decompaction of myelin, altered myelin structure, and swelling of myelinated axons are persistent features of the chronic phases of secondary degeneration and likely contribute to progressive loss of visual function.

Cell encapsulation therapies involve the implantation of cells that secrete a therapeutic factor to provide clinical benefits. The transplanted cells are protected from immunorejection via encapsulation in a semipermeable membrane. This treatment strategy was originally investigated as a method for protecting pancreatic islets from immunorejection, thus allowing them to secrete insulin as a chronic treatment for diabetes. Since then a significant body of work has been conducted in developing cell encapsulation therapies to treat a variety of different diseases. Many of these conditions involve neurodegeneration, such as Alzheimer's and Parkinson's disease, as cell encapsulation therapies have proven to be particularly suitable for delivering therapeutics to the central nervous system. This is mainly because they offer chronic delivery of a therapeutic and can be implanted proximal to the affected tissue, bypassing the blood brain barrier, which is impermeable to many agents. Whilst these therapies are not yet widely available in the clinic, promising results have been obtained in several advanced clinical trials and further developmental work is currently underway. This review specifically examines the development of encapsulated cell therapies as treatments for neurological and sensory diseases and evaluates the challenges that are yet to be overcome before they can be made available for clinical use.

Secondary degeneration is a serious consequence of traumatic injury to the central nervous system (CNS) and involves the progressive loss of neurons and function. However, while disruption to myelin has been observed in spared axons, the ultrastructural abnormalities that occur in myelin and axons spatially separated from the primary injury and susceptible exclusively to secondary degeneration are unknown. We used a model of secondary degeneration in which the dorsal aspect of rat optic nerve (ON) was transected leaving the central/ventral ON undamaged, but vulnerable to secondary degeneration. Transmission electron microscopy of the central/ventral ON at 1 and 3 months was used to quantify secondary changes in axon diameter, myelin sheath thickness and morphology, compared to normal animals. Three months after partial ON transection, cross-sectional nerve area at the injury site was increased (p ≤ 0.05), and changes in axons and myelin sheaths were detected in the central/ventral ON. Although myelin sheath thickness remained normal at both time points, average axon diameter significantly increased at 3 months. The density of the total axon population was decreased by 1 month, reflecting loss of retinal ganglion cells as previously published, with a decrease in the density of normally-myelinated axons, but an increase in unmyelinated axon density (p ≤ 0.05). Myelin basic protein immunoreactivity and fluoromyelin staining were also significantly reduced. Within four subpopulations of abnormally-myelinated axons, there was: no change in lightly-myelinated axons; an increase in axons with excessive myelination (at 1 month); and an increase in the density of axons with partial and fully-decompacted myelin (at 3 months, p ≤ 0.05). Chronic axon swelling and myelin sheath compaction defects are features of secondary degeneration, and may contribute to the reported loss of ON function following partial transection.

Traumatic injury to the central nervous system (CNS) is accompanied by the spreading damage of secondary degeneration, resulting in further loss of neurons and function. Partial transection of the optic nerve (ON) has been used as a model of secondary degeneration, in which axons of retinal ganglion cells in the ventral ON are spared from initial dorsal injury, but are vulnerable to secondary degeneration. We have recently demonstrated that early after partial ON injury, oxidative stress spreads through the ventral ON vulnerable to secondary degeneration via astrocytes, and persists in the nerve in aggregates of cellular debris. In this study, we show that diffuse transcranial irradiation of the injury site with far red to near infrared (NIR) light (WARP 10 LED array, center wavelength 670 nm, irradiance 252 W/m(-2), 30 min exposure), as opposed to perception of light at this wavelength, reduced oxidative stress in areas of the ON vulnerable to secondary degeneration following partial injury. The WARP 10 NIR light treatment also prevented increases in NG-2-immunopositive oligodendrocyte precursor cells (OPCs) that occurred in ventral ON as a result of partial ON transection. Importantly, normal visual function was restored by NIR light treatment with the WARP 10 LED array, as assessed using optokinetic nystagmus and the Y-maze pattern discrimination task. To our knowledge, this is the first demonstration that 670-nm NIR light can reduce oxidative stress and improve function in the CNS following traumatic injury in vivo.

PURPOSE: After partial optic nerve (ON) injury, intact retinal ganglion cells (RGCs) undergo secondary death, but the topographic distribution of this death is unknown, and it is unclear which cell death pathways are involved. Although the calcium channel blocker lomerizine reduces RGC death after partial ON injury, it is unknown whether this drug alleviates necrotic or apoptotic death. METHODS: The dorsal ON was transected in adult Piebald-Virol-Glaxo (PVG) rats, and the site of secondary RGC death was determined using anterograde and retrograde DiI tracing. RGC death was assessed at 2 and 3 weeks. Retrograde tracing with fluorogold injected into the superior colliculus 3 days before euthanatization was used to identify RGCs undergoing secondary death. Overall cell loss was quantified using betaIII-tubulin immunohistochemistry. Lomerizine (30 mg/kg, oral) or vehicle was given twice daily, and retinal wholemounts were analyzed for necrotic morphology (nucleic acid stain) or anticleaved caspase-3 expression at 2 and 3 weeks. RESULTS: Ventral retina was identified as the site of secondary RGC death, and central and dorsal retinae were defined as sites of both primary and secondary death. Overall RGC loss occurred by 2 weeks in central and ventral retina (P < 0.05) and by 3 weeks in dorsal retina (P < 0.05). Secondary RGC death was characterized mainly by necrotic morphology, with caspase-3 expression in some RGCs. Lomerizine reduced secondary necrosis at 2 weeks and secondary caspase-3 expression at 3 weeks. CONCLUSIONS: Lomerizine had differential effects on necrotic and apoptotic death with time, but its inability to completely prevent secondary death suggests that full neuroprotection will require combinatorial treatments.