Evaluation of Stem Cell Laden Collagen + Polycaprolactone + Multi-Walled Carbon Nano-Tubes Nano-Neural Scaffold with and Without Insulin Like Growth Factor-I For Sciatic Nerve Regeneration Post Crush Injury in Wistar Rats.

BACKGROUND/AIMS: All body functions are activated, synchronized and controlled by a substantial, complex network, the nervous system. Upon injury, pathophysiology of the nerve injury proceeds through different paths. The axon may undergo a degenerative retraction from the site of injury for a short distance unless the injury is near to the cell body, in which case it continues to the soma and undergoes retrograde neuronal degeneration. Otherwise, the distal section suffers from Wallerian degeneration, which is marked by axonal swelling, spheroids, and cytoskeleton degeneration. The objective of the study was to evaluate the potential of mesenchymal stem cell laden neural scaffold and insulin-like growth factor I (IGF-I) in nerve regeneration following sciatic nerve injury in a rat model. METHODS: The animals were anaesthetized and a cranio-lateral incision over left thigh was made. Sciatic nerve was exposed and crush injury was introduced for 90 seconds using haemostat at second locking position. The muscle and skin were sutured in routine fashion and thus the rat model of sciatic crush injury was prepared. The animal models were equally distributed into 5 different groups namely A, B, C, D and E and treated with phosphate buffer saline (PBS), carbon nanotubes based neural scaffold only, scaffold with IGF-I, stem cell laden scaffold and stem cell laden scaffold with IGF-I respectively. In vitro scaffold testing was performed. The nerve regeneration was assessed based on physico-neuronal, biochemical, histopathological examination, and relative expression of NRP-1, NRP-2 and GAP-43 and scanning electron microscopy. RESULTS: Sciatic nerve injury model with crush injury produced for 90 seconds was standardized and successfully used in this study. All the biochemical parameters were in normal range in all the groups indicating no scaffold related changes. Physico-neuronal, histopathological, relative gene expression and scanning electron microscopy observations revealed appreciable nerve regeneration in groups E and D, followed by C and B. Restricted to no regeneration was observed in group A. CONCLUSION: Carbon nanotubes based scaffold provided electro-conductivity for proper neuronal regeneration while rat bone marrow-derived mesenchymal stem cells were found to induce axonal sprouting, cellular transformation; whereas IGF-I induced stem cell differentiation, myelin synthesis, angiogenesis and muscle differentiation.

Long-term tactile hypersensitivity after nerve crush injury in mice is characterized by the persistence of intact sensory axons.

ABSTRACT: Traumatic peripheral nerve injuries are at high risk of neuropathic pain for which novel effective therapies are urgently needed. Preclinical models of neuropathic pain typically involve irreversible ligation and/or nerve transection (neurotmesis). However, translation of findings to the clinic has so far been unsuccessful, raising questions on injury model validity and clinically relevance. Traumatic nerve injuries seen in the clinic commonly result in axonotmesis (ie, crush), yet the neuropathic phenotype of "painful" nerve crush injuries remains poorly understood. We report the neuropathology and sensory symptoms of a focal nerve crush injury using custom-modified hemostats resulting in either complete ("full") or incomplete ("partial") axonotmesis in adult mice. Assays of thermal and mechanically evoked pain-like behavior were paralleled by transmission electron microscopy, immunohistochemistry, and anatomical tracing of the peripheral nerve. In both crush models, motor function was equally affected early after injury; by contrast, partial crush of the nerve resulted in the early return of pinprick sensitivity, followed by a transient thermal and chronic tactile hypersensitivity of the affected hind paw, which was not observed after a full crush injury. The partially crushed nerve was characterized by the sparing of small-diameter myelinated axons and intraepidermal nerve fibers, fewer dorsal root ganglia expressing the injury marker activating transcription factor 3, and lower serum levels of neurofilament light chain. By day 30, axons showed signs of reduced myelin thickness. In summary, the escape of small-diameter axons from Wallerian degeneration is likely a determinant of chronic pain pathophysiology distinct from the general response to complete nerve injury.

The Optic Nerve Crush Injury Paradigm in African Turquoise Killifish to Study Axonal Regeneration in an Aged Environment.

In our graying world population, we are increasingly facing brain injuries and age-associated neurodegenerative diseases, which are often characterized by axonal pathology. Here, we propose the killifish visual/retinotectal system as a model for investigating central nervous system repair, more specifically axonal regeneration, in an aging context. We first describe an optic nerve crush (ONC) injury paradigm in killifish to induce and study both de- and regeneration of retinal ganglion cells (RGCs) and their axons. Subsequently, we summarize several methods for mapping different steps of the regenerative process-namely, axonal regrowth and synapse reformation-using retro- and anterograde tracing methods, (immuno)histochemistry, and morphometrical analyses.

The effects of curcumin and blueberry on axonal regeneration after peripheral nerve injury.

The purpose of this study was to analyze the axonal regeneration and therapeutic effects of curcumin and blueberry administration following peripheral nerve injury using stereological, electron microscopic and electrophysiological methods. Animals in were assigned into one of four groups - control (Cont), injury (Inj), injury+curcumin (Cur) and injury+blueberry (Blue). Following the induction of sciatic nerve crush injury (75 Newtons for 5 s) in the Inj, Cur, and Blue groups, the rats in the Cur group received intraperitoneal injection of 30 mg/kg curcumin (Sigma C1386) and the rats in the Blue group received 4 g/kg blueberry by gavage over a four-week period. The rats in the Cont and Inj groups were not exposed to any substance. All animals were given standard chow. Sciatic functional index analyses were performed on the 14th and 28th days after injury, and electromyography (EMG) results were recorded. Stereological analysis of the nerve was performed under light microscopy. Light and electron microscopies were used for the histopathological evaluation of the sciatic nerve. Analysis of myelinated axon numbers revealed no significant differences between the Inj group and the Cur and Blue groups. However, a significant difference was observed between the Blue and Inj groups in terms of axonal areas. EMG test results differed between the Blue and the Inj groups (p < 0.05), but no significant difference was observed between the Inj and Cur groups. Electron microscopic analysis revealed protective effects of curcumin and blueberry treatment after injury. The use of the curcumin and blueberry may represent a supportive approach to the protection of nerve fibers after peripheral nerve crush injury.

Functional Gait Assessment Using Manual, Semi-Automated and Deep Learning Approaches Following Standardized Models of Peripheral Nerve Injury in Mice.

Objective: To develop a standardized model of stretch−crush sciatic nerve injury in mice, and to compare outcomes of crush and novel stretch−crush injuries using standard manual gait and sensory assays, and compare them to both semi-automated as well as deep-learning gait analysis methods. Methods: Initial studies in C57/Bl6 mice were used to develop crush and stretch−crush injury models followed by histologic analysis. In total, 12 eight-week-old 129S6/SvEvTac mice were used in a six-week behavioural study. Behavioral assessments using the von Frey monofilament test and gait analysis recorded on a DigiGait platform and analyzed through both Visual Gait Lab (VGL) deep learning and standardized sciatic functional index (SFI) measurements were evaluated weekly. At the termination of the study, neurophysiological nerve conduction velocities were recorded, calf muscle weight ratios measured and histological analyses performed. Results: Histological evidence confirmed more severe histomorphological injury in the stretch−crush injured group compared to the crush-only injured group at one week post-injury. Von Frey monofilament paw withdrawal was significant for both groups at week one compared to baseline (p < 0.05), but not between groups with return to baseline at week five. SFI showed hindered gait at week one and two for both groups, compared to baseline (p < 0.0001), with return to baseline at week five. Hind stance width (HSW) showed similar trends as von Frey monofilament test as well as SFI measurements, yet hind paw angle (HPA) peaked at week two. Nerve conduction velocity (NCV), measured six weeks post-injury, at the termination of the study, did not show any significant difference between the two groups; yet, calf muscle weight measurements were significantly different between the two, with the stretch−crush group demonstrating a lower (poorer) weight ratio relative to uninjured contralateral legs (p < 0.05). Conclusion: Stretch−crush injury achieved a more reproducible and constant injury compared to crush-only injuries, with at least a Sunderland grade 3 injury (perineurial interruption) in histological samples one week post-injury in the former. However, serial behavioral outcomes were comparable between the two crush groups, with similar kinetics of recovery by von Frey testing, SFI and certain VGL parameters, the latter reported for the first time in rodent peripheral nerve injury. Semi-automated and deep learning-based approaches for gait analysis are promising, but require further validation for evaluation in murine hind-limb nerve injuries.

Human Multipotent Mesenchymal Stromal Cell-Derived Extracellular Vesicles Enhance Neuroregeneration in a Rat Model of Sciatic Nerve Crush Injury.

Peripheral nerve injury remains a serious problem for medicine, with no effective method of treatment at the moment. The most prominent example of this problem is neonatal brachial plexus palsy, which results from the stretching of the brachial plexus nerves in the birth or perinatal period. Multipotent mesenchymal cells (MSCs) and the extracellular vesicles (EVs) they produce are known to have a marked neuroprotective effect in central nervous system injuries. We suggested that the use of MSCs-derived EVs may be an effective approach to the regeneration of peripheral nerves after injury. Sciatic nerve injury was modeled in rats via crushing, and then a gel containing MSCs-EVs was applied to the injured area. After 15 and 30 days, a histological, physiological, and functional assessment of nerve, dorsal root ganglia (DRG), and innervated muscles' recovery was performed. Transplantation of EVs to the area of sciatic nerve injury significantly reduced muscle atrophy as compared to the control group. Functional recovery of the innervated muscles, as measured by the extensor postural thrust test, was revealed 30 days after the surgery. We associate the obtained results with EVs-induced neuroprotective mechanisms, which were expressed in a decrease in apoptotic neuronal death and an increase in regeneration-associated proteins NF-200 and GAP-43, as well as in DRG and damaged nerve. We suggest that the therapeutic scheme we used is efficient for the treatment of acute peripheral nervous system injuries and can be transferred to the clinics. However, additional studies are required for a more detailed analysis of neuroprotection mechanisms.

Effects of bee honey on promotion of peripheral nerve regeneration in an experimental model of nerve crush injury.

Peripheral nerve injuries are commonly encountered within clinical settings because of accidental trauma. This study aimed to examine the therapeutic effect of bee honey on peripheral nerve crush injury through a histological and physiological perspective. In this study, forty Wistar rats were divided into four groups. Rats were subjected to surgical operations to expose the sciatic nerve. Animals of the first group were operated without inducing any lesion to the nerve. The other three groups were subjected to induction of nerve crush injury. Two groups of them were treated with honey solution locally and intraperitoneally respectively. The other group served as injured nontreated group. Two physiological tests were performed to examine the living animals' nerve functions. At the end of the experimental period, the rats were sacrificed, and samples from the sciatic nerve and gastrocnemius muscle were obtained for histological, immunohistochemical and ultrastructural examination. Physiological indicators and structural investigations demonstrated considerable amelioration of the function and structure of nerves and muscles in the two treated groups compared with the injured nontreated group. The findings indicate that the bee honey has a curative effect on the peripheral nerve crush injury in the rat model.

Potential Effects of Stem Cells Derived from the Peripheral Nerve and Adipose Tissue after the Nerve Crush Injury in Control and Obese Rats.

Aim of this study is to investigate effects of stem cells derived from the peripheral nerve and adipose tissues following the nerve crush injury in control and obese rats. For this aim, 41 Wistar Albino female rats were separated into eight equal groups; non-obese control (NOC) obese control (OC), non-obese injury (NOH), obese injury (OH), non-obese adipose (NOY), obese adipose (OY), non-obese nerve (NOPS), obese nerve (OPS). At the end of 8 weeks, all experimental animals without control groups were subjected to nerve crush procedure and sciatic nerve or fat stem cell homogenates were injected on the treatment group rats, and then, recovery process has been observed and histopathological, stereological, electrophysiological analyses and bioinformatic evaluation were made on removed sciatic nerves. Stereological results showed that adipose homogenate gave more successful results than peripheral nerve homogenates in the NOY group in comparison to the NOPS group in terms of myelinated axon number. Peripheral nerve homogenate has shown more successful results in the OPS group in comparison to the OY group. The number of unmyelinated axons was increased following treatment with adipose tissue homogenate in NOY and OY groups. In terms of myelin sheath thickness; we detected that treatments by peripheral nerve and especially adipose tissue homogenates lead to increase in the thickness of the axons of the peripheral nerves belong to the control and obese injury groups. All results showed that mesenchymal stem cell treatment by fresh tissue homogenates is successful in peripheral nerve regeneration and fat tissue is a considerable source of the stem cells for clinical applications.

Safety and efficacy of an injectable nerve-specific hydrogel in a rodent crush injury model.

INTRODUCTION/AIMS: While the peripheral nervous system has the inherent ability to recover following injury, results are often unsatisfactory, resulting in permanent functional deficits and disability. Therefore, methods that enhance regeneration are of significant interest. The present study investigates an injectable nerve-tissue-specific hydrogel as a biomaterial for nerve regeneration in a rat nerve crush model. METHODS: Nerve-specific hydrogels were injected into the subepineurial space in both uninjured and crushed sciatic nerves of rats to assess safety and efficacy, respectively. The animals were followed longitudinally for 12 wk using sciatic functional index and kinematic measures. At 12 wk, electrophysiologic examination was also performed, followed by nerve and muscle histologic assessment. RESULTS: When the hydrogel was injected into an uninjured nerve, no differences in sciatic functional index, kinematic function, or axon counts were observed. A slight reduction in muscle fiber diameter was observed in the hydrogel-injected animals, but overall muscle area and kinematic function were not affected. Hydrogel injection following nerve crush injury resulted in multiple modest improvements in sciatic functional index and kinematic function with an earlier return to normal function observed in the hydrogel treated animals as compared to untreated controls. While no improvements in supramaximal compound motor action potential were observed in hydrogel treated animals, increased axon counts were observed on histologic assessment. DISCUSSION: These improvements in functional and histologic outcomes in a rapidly and fully recovering model suggest that injection of a nerve-specific hydrogel is safe and has the potential to improve outcomes following nerve injury.

Comparing effects of L-carnitine and sildenafil citrate on histopathologic recovery from sciatic nerve crush injury in female albino rats.

BACKGROUND: The sciatic nerve is a peripheral nerve and is more vulnerable to compression with subsequent short- or long-term neuronal dysfunction. The current study was designed to elucidate the possible ameliorative effect of L-carnitine and sildenafil (SIL) on sciatic nerve crush injury. We sought to determine the effects of L-carnitine, a neuroprotective and a neuro-modulatory agent, and SIL citrate, a selective peripheral phosphodiesterases inhibitor, on modulating neuro-degenerative changes due to sciatic nerve compression. MATERIALS AND METHODS: The comparative effect of L-carnitine (at an oral dose of 20 mg/kg/day) or SIL citrate (20 mg/kg/day orally) administration for 21 days was studied in a rat model of sciatic nerve compression. Sciatic nerve sections were subjected to biochemical, histological, ultrastructure, and immunohistochemical studies to observe the effects of these treatments on neurofilament protein. RESULTS: The sciatic nerve crush injury group (group II) showed a significant decrease in tissue catalase (CAT), superoxide dismutase (SOD) and increase in malondialdehyde (MDA) as compared to control group (p < 0.01). Histological changes in the form of degenerated and vacuolated axoplasm with areas of nerve fibre loss and pyknotic nuclei were reported. The blood vessels were dilated, congested with areas of haemorrhage and mononuclear cell infiltration. Histo-morphometrically, a statistically significant reduction in the nerve fibres' number, mean axon cross-sectional area, myelin sheath thickness and a significant increase in collagen fibres' percentage (p < 0.05) as compared to control group. Immunohistochemically, neurofilament protein was significantly downregulated as proved by a significant reduction in mean area per cent of neurofilament expression. L-carnitine ameliorated the studied parameters through its neuroprotective effect while SIL, a selective peripheral phosphodiesterases (PDE-5) inhibitor, improved crush injury parameters but with less extent than L-carnitine. CONCLUSIONS: These findings indicate the valuable effects of L-carnitine administration compared to that of SIL citrate in alleviating the serious debilitating effects of sciatic nerve crush injury. Our results provide a new insight into the scope of neuroprotective and neuro-regenerative effects of L-carnitine in a sciatic nerve compression model.

Insulin Topical Application for Wound Healing in Nondiabetic Patients.

BACKGROUND: Low-cost and safe strategies to improve wound healing will be of great social and economic value. The goal of this pilot clinical trial is aimed at analyzing how effective insulin therapy is at healing wounds in nondiabetic people. METHODS: In this protocol research, 346 individuals were included. Patients were divided as 2 groups at random: experimental patients were given a ten-unit answer. For each 10 cm2 of wound, insulin was injected in solution with 1 mL 0.9 percent saline, whereas the control group got a standard dressing with normal saline. RESULTS: During the therapy period, no adverse effects were reported. After insulin therapy, no substantial insulin-related side effects were reduced. After 10 days of therapy, the experimental group's granulation tissue coverage rate and thickness were considerably improved as compared to control. Furthermore, a momentous difference in the occurrence of wound bleeding and suppurative wounds between the two groups (P = 0.05). CONCLUSION: The results of this pilot research suggest that insulin injections could harmless and effective alternative therapy for wound healing in nondiabetic individuals and that larger, placebo-controlled trials are needed to evaluate effectiveness and safety of insulin treatment in wound healing patients.

Diterpene Ginkgolides Meglumine Injection inhibits apoptosis induced by optic nerve crush injury via modulating MAPKs signaling pathways in retinal ganglion cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Diterpene Ginkgolides Meglumine Injection (DGMI) is made of extracts from Ginkgo biloba L, including Ginkgolides A, B, and K and some other contents, and has been widely used as the treatment of cerebral ischemic stroke in clinic. It can be learned from the "Compendium of Materia Medica" that Ginkgo possesses the effect of "dispersing toxin". The ancient Chinese phrase "dispersing toxin" is now explained as elimination of inflammation and oxidative state in human body. And it led to the original ideas for today's anti-oxidation studies of Ginkgo in apoptosis induced by optic nerve crush injury. AIM OF THE STUDY: To investigate the underlying molecular mechanism of the DGMI in retinal ganglion cells (RGCs) apoptosis. MATERIALS AND METHODS: TUNEL staining was used to observe the anti-apoptotic effects of DGMI on the adult rat optic nerve injury (ONC) model, and flow cytometry and hoechst 33,342 staining were used to observe the anti-apoptotic effects of DGMI on the oxygen glucose deprivation (OGD) induced RGC-5 cells injury model. The regulation of apoptosis and MAPKs pathways were investigated with Immunohistochemistry and Western blotting. RESULTS: This study demonstrated that DGMI is able to decrease the conduction time of F-VEP and ameliorate histological features induced by optic nerve crush injury in rats. Immunohistochemistry and TUNEL staining results indicated that DGMI can also inhibit cell apoptosis via modulating MAPKs signaling pathways. In addition, treatment with DGMI markedly improved the morphological structures and decreased the apoptotic index in RGC-5 cells. Mechanistically, DGMI could significantly inhibit cell apoptosis by inhibiting p38, JNK and Erk1/2 activation. CONCLUSION: The study shows that DGMI and ginkgolides inhibit RGCs apoptosis by impeding the activation of MAPKs signaling pathways in vivo and in vitro. Therefore, the present study provided scientific evidence for the underlying mechanism of DGMI and ginkgolides on optic nerve crush injury.

Investigation of Neuropathology after Nerve Release in Chronic Constriction Injury of Rat Sciatic Nerve.

Peripheral compressive neuropathy causes significant neuropathic pain, muscle weakness and prolong neuroinflammation. Surgical decompression remains the gold standard of treatment but the outcome is suboptimal with a high recurrence rate. From mechanical compression to chemical propagation of the local inflammatory signals, little is known about the distinct neuropathologic patterns and the genetic signatures after nerve decompression. In this study, controllable mechanical constriction forces over rat sciatic nerve induces irreversible sensorimotor dysfunction with sustained local neuroinflammation, even 4 weeks after nerve release. Significant gene upregulations are found in the dorsal root ganglia, regarding inflammatory, proapoptotic and neuropathic pain signals. Genetic profiling of neuroinflammation at the local injured nerve reveals persistent upregulation of multiple genes involving oxysterol metabolism, neuronal apoptosis, and proliferation after nerve release. Further validation of the independent roles of each signal pathway will contribute to molecular therapies for compressive neuropathy in the future.

Citrus Naringenin Increases Neuron Survival in Optic Nerve Crush Injury Model by Inhibiting JNK-JUN Pathway.

Traumatic nerve injury activates cell stress pathways, resulting in neuronal death and loss of vital neural functions. To date, there are no available neuroprotectants for the treatment of traumatic neural injuries. Here, we studied three important flavanones of citrus components, in vitro and in vivo, to reveal their roles in inhibiting the JNK (c-Jun N-terminal kinase)-JUN pathway and their neuroprotective effects in the optic nerve crush injury model, a kind of traumatic nerve injury in the central nervous system. Results showed that both neural injury in vivo and cell stress in vitro activated the JNK-JUN pathway and increased JUN phosphorylation. We also demonstrated that naringenin treatment completely inhibited stress-induced JUN phosphorylation in cultured cells, whereas nobiletin and hesperidin only partially inhibited JUN phosphorylation. Neuroprotection studies in optic nerve crush injury mouse models revealed that naringenin treatment increased the survival of retinal ganglion cells after traumatic optic nerve injury, while the other two components had no neuroprotective effect. The neuroprotection effect of naringenin was due to the inhibition of JUN phosphorylation in crush-injured retinal ganglion cells. Therefore, the citrus component naringenin provides neuroprotection through the inhibition of the JNK-JUN pathway by inhibiting JUN phosphorylation, indicating the potential application of citrus chemical components in the clinical therapy of traumatic optic nerve injuries.

N-acetylcysteine maintains penile length and erectile function in bilateral cavernous nerve crush rat model by reducing penile fibrosis.

Penile length shortening and erectile dysfunction are common complications after radical prostatectomy. Various methods have been used to maintain erectile function, but less attention has been paid to preserving penis length. N-acetylcysteine (NAC) has the effect of antioxidation and antifibrotic, which may be beneficial to improve those postoperative complications. This study investigated the effect of NAC on maintaining the penile length and the erectile function after bilateral cavernous nerve crush (BCNC) and its underlying mechanism. Twenty-four male rats were randomly divided into three groups: control group, BCNC group, and BCNC + NAC group. NAC or equal volume of saline was daily administrated by intragastric gavage for 4 weeks. The initial and end penile lengths were measured. Intracavernosal pressure/mean arterial pressure (ICP/MAP) ratio was calculated to assess erectile function. Hematoxylin-eosin staining, Masson's trichrome staining, immunohistochemistry, and Western blot were performed to explore cellular and molecular changes of the penis. Compared to the BCNC group, the penile length, ICP/MAP ratio and smooth muscle/collagen ratio in the BCNC + NAC group were improved significantly (all P < 0.05), and the expressions of endothelial nitric oxide synthase, α-smooth muscle actin, glutathione, and glutathione peroxidase 1 were significantly increased after NAC treated (all P < 0.05), along with the decreased expressions of hypoxia-inducible factor-1α, transforming growth factor-ß1, collagen I, collagen III, collagen IV, malonaldehyde, and lysine oxidase (all P < 0.05). This study demonstrated that NAC could maintain penile length and partly improve erectile function. Possible mechanism is directly and/or indirectly related to antihypoxic and antifibrosis.

Reactive Fibroblasts in Response to Optic Nerve Crush Injury.

Traumatic optic neuropathy leads to bidirectional degeneration of retinal ganglion cells and axons and results in optic nerve scaring, which inhibits the regeneration of damaged axons. Compared with its glial counterpart, the fibrotic response causing nerve scar tissue is poorly permissive to axonal regeneration. Using collagen1α1-GFP reporter mice, we characterize the development of fibrotic scar formation following optic nerve crush injury. We observe that perivascular collagen1α1 cells constitute a major cellular component of the fibrotic scar. We demonstrate that extracellular molecules and monocytes are key factors contributing to the pathogenesis of optic nerve fibrotic scar formation, with a previously unrecognized encapsulation of this scar. We also characterize the distribution of collagen1α1 cells in the retina after optic nerve crush injury based on in vivo and whole-mount retinal imaging. Our results identify collagen1α1 cells as a major component of fibrotic scarring following ONC and are a potential molecular target for promoting axonal regeneration after optic nerve injury.

Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury.

After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.

Comparison of MR findings of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model.

PURPOSE: The treatment strategy is different for acute traumatic peripheral nerve injury and acute compressive neuropathy. This study aimed to compare magnetic resonance imaging (MRI) features of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model. MATERIALS AND METHODS: Twenty female Sprague-Dawley rats were divided into two groups. In the crush injury group (n = 10), the unilateral sciatic nerve was crushed using forceps to represent acute traumatic peripheral nerve injury. In the compression injury group (n = 10), the unilateral sciatic nerve was ligated using silk to represent acute compressive neuropathy. The MRI of eight rats from each group were acquired on postoperative days 3 and 10. Fat-suppressed T2-weighted images were acquired. Changes in the injured nerve were divided into three grades. A Fisher's exact test was used to compare the changes in the nerves of the two groups. Histological staining and a western blot analysis were performed on one rat in each group on day 3. Neurofilament, myelin basic protein (MBP), and p75NTR staining were performed. Expression of neurofilament, MBP, p75NTR, and c-jun was evaluated by western blot analysis. RESULTS: MR neurography revealed substantial nerve changes in the compression injury group compared with the crush injury group at two-time points (p = 0.001 on day 3, p = 0.026 on day 10). The histopathological analysis indicated the destruction of the axon and myelin, mainly at the injury site and the distal portion of the injury in the crush injury group. It was prominent in the proximal portion, the injury site, and the distal portion of the injury in the compression injury group. The degree of axonal and myelin destruction was more pronounced in the compression injury group than in the crush injury group. CONCLUSION: MR neurography showed prominent and long-segmental changes associated with the injured nerve in acute compressive neuropathy compared with acute traumatic peripheral nerve injury.

Reduced Dendritic Spines in the Visual Cortex Contralateral to the Optic Nerve Crush Eye in Adult Mice.

Purpose: To determine alteration of dendritic spines and associated changes in the primary visual cortex (V1 region) related to unilateral optic nerve crush (ONC) in adult mice. Methods: Adult unilateral ONC mice were established. Retinal nerve fiber layer (RNFL) thickness was measured by spectral-domain optical coherence tomography. Visual function was estimated by flash visual evoked potentials (FVEPs). Dendritic spines were observed in the V1 region contralateral to the ONC eye by two-photon imaging in vivo. The neurons, reactive astrocytes, oligodendrocytes, and activated microglia were assessed by NeuN, glial fibrillary acidic protein, CNPase, and CD68 in immunohistochemistry, respectively. Tropomyosin receptor kinase B (TrkB) and the markers in TrkB trafficking were estimated using western blotting and co-immunoprecipitation. Transmission electron microscopy and western blotting were used to evaluate autophagy. Results: The amplitude and latency of FVEPs were decreased and delayed at 3 days, 1 week, 2 weeks, and 4 weeks after ONC, and RNFL thickness was decreased at 2 and 4 weeks after ONC. Dendritic spines were reduced in the V1 region contralateral to the ONC eye at 2, 3, and 4 weeks after ONC, with an unchanged number of neurons. Reactive astrocyte staining was increased at 2 and 4 weeks after ONC, but oligodendrocyte and activated microglia staining remained unchanged. TrkB was reduced with changes in the major trafficking proteins, and enhanced autophagy was observed in the V1 region contralateral to the ONC eye. Conclusions: Dendritic spines were reduced in the V1 region contralateral to the ONC eye in adult mice. Reactive astrocytes and decreased TrkB may be associated with the reduced dendritic spines.

Death scene investigation and autopsy proceedings in identifying the victims of the terror attack on the Breitscheidplatz in Berlin 19th December 2016.

We describe and discuss the forensic mission after the terrorist attack on the Breitscheidplatz in Berlin on 19th December 2016, focusing on co-operation with police authorities, and the injury patterns of the deceased. Even after massive blunt trauma, severe injury patterns are often unrecognizable by visual inspection of the body ("Casper's sign"), which could instill false security among rescuers or, as happened on the Breitscheidplatz, may lead to distress or even trauma in rescue personnel when obviously primarily uninjured patients die suddenly.