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.

Early Results of Supporting Free Flap Coverage of Mangled Lower Extremities with Long Saphenous Arteriovenous Loop Grafts.

BACKGROUND: The ability to salvage the mangled lower extremity is both technically challenging and time consuming. It requires the collaborative efforts among multiple surgical specialties in addition to comprehensive post-traumatic wound follow-up. Our institution has integrated a dynamic effort among these specialists in the planning and facilitating a successful limb salvage program with creation of a mangled extremity algorithm. An integral part in this process is the vascular inflow to prepare coverage for large tissue defects lacking adequate recipient targets. Utilization of long saphenous arteriovenous (AV) loop has been cited with minimal data available using larger inflow vessels in the acute trauma setting. We performed a retrospective review and describe our early experience using our protocol with AV loop creation with free flap reconstruction to salvage traumatic leg injuries. Using the data, we sought to develop a mangled extremity protocol for trauma centers to guide mangled limb salvage. METHODS: Since June 2016, 398 patients were admitted to our level II trauma facility with isolated traumatic wounds to the lower extremities. Thirty-one limbs were deemed mangled in which 21 received primary amputations due to multiple factors. Ten patients admitted from the trauma service with isolated mangled lower extremities injuries were identified for review. All 10 patients sustained severe crush injuries with large soft tissue defects and decreased perfusion for healing but deemed salvageable by multispecialty assessment. Mangled extremity severity scores were tabulated. Patients age ranged from 21-44 years, with 8 men and 2 women. Repeated debridements until successful sterilization of the wounds were accomplished. Ten long saphenous vein AV loops were anastomosed to the at or above knee popliteal vessels for free flap reconstruction. All patients were followed post-AV loop creation for vascular complications and wound assessments. RESULTS: All 10 patients had sterilization of the wounds with repair of the fracture site before vascular reconstruction. Mean debridement to surgical site sterilization was 4.3 washouts (range 2-7). Successful AV loop creation with long saphenous vein was completed in 100% of patients without vascular complications nor steal events. Free flap tissue transfers directly connected to the loop were completed using 6 rectus abdominis, 3 latissimus dorsi, and 1 anterior thigh graft within 10 days of its creation. Patency rates of the AV loop was 100% with 10 successful flap transfers and 90% amputation free survival. One flap did not survive due to recurrent bacterial infection of the hardware. The 9 patients with successful procedures reached preoperative ambulatory status within 3 months after their final surgery. At 24 months follow-up, 90% amputation free survival is still maintained. CONCLUSIONS: Although a small patient cohort, utilization of long saphenous vein AV loop is successful as a bridge to free flap transfer for isolated mangled lower extremities. Development and incorporation of our mangled extremity protocol to guide limb salvage has proven successful in our early experience. Long-term data need to be complied to assess patency of the free flap transfer and quality of life outcomes.

Diffusion Magnetic Resonance Imaging Predicts Peripheral Nerve Recovery in a Rat Sciatic Nerve Injury Model.

BACKGROUND: Nerve regeneration after an injury should occur in a timely fashion for function to be restored. Current methods cannot monitor regeneration prior to muscle reinnervation. Diffusion tensor imaging has been previously shown to provide quantitative indices after nerve recovery. The goal of this study was to validate the use of this technology following nerve injury via a series of rat sciatic nerve injury/repair studies. METHODS: Sprague-Dawley rats were prospectively divided by procedure (sham, crush, or cut/repair) and time points (1, 2, 4, and 12 weeks after surgery). At the appropriate time point, each animal was euthanized and the sciatic nerve was harvested and fixed. Data were obtained using a 7-Tesla magnetic resonance imaging system. For validation, findings were compared to behavioral testing (foot fault asymmetry and sciatic function index) and cross-sectional axonal counting of toluidine blue-stained sections examined under light microscopy. RESULTS: Sixty-three rats were divided into three treatment groups (sham, n = 21; crush, n = 23; and cut/repair, n = 19). Fractional anisotropy was able to differentiate between recovery following sham, crush, and cut/repair injuries as early as 2 weeks (p < 0.05), with more accurate differentiation thereafter. More importantly, the difference in anisotropy between distal and proximal regions recognized animals with successful and failed recoveries according to behavioral analysis, especially at 12 weeks. In addition, diffusion tension imaging-based tractography provided a visual representation of nerve continuity in all treatment groups. CONCLUSIONS: Diffuse tensor imaging is an objective and noninvasive tool for monitoring nerve regeneration. Its use could facilitate earlier detection of failed repairs to potentially help improve outcomes.

Urethral dysfunction and therapeutic effects of a PDE 5 inhibitor (tadalafil) in a rat model of detrusor underactivity induced by pelvic nerve crush injury.

AIMS: The urethral dysfunction produced by a rat model of peripheral neurogenic detrusor underactivity (DU) using pelvic nerve crush (PNC) injury was characterized and then tested with the administration of tadalafil, a phosphodiesterase type 5 (PDE 5) inhibitor. METHODS: Ten days after producing PNC rats, awake cystometrograms (CMGs) and isovolumetric cystometrograms with urethral perfusion pressure (IC-UPP) measurements were performed. Also, in control rats, IC-UPP was recorded before and after intravenous atropine administration to determine if the reduction of bladder contraction pressure affects urethral relaxation during voiding. Then, CMG and IC-UPP measurements in PNC rats were recorded after intravenous administration of tadalafil. Lastly, real-time polymerase chain reaction was used to measure transcript levels of neuronal nitric oxide synthases (nNOS), endothelial nitric oxide synthases, and PDE 5 in urethral specimens from PNC and control rats. RESULTS: PNC rats demonstrated the characteristics of DU in CMG. Also, PNC rats exhibited significant decreases in isovolumetric bladder contraction amplitudes and urethral relaxation. Atropine attenuated the amplitude of isovolumetric bladder contractions; however, atropine did not affect urethral relaxation in control rats. Tadalafil decreased postvoid residual and increased voiding efficiency without changing bladder contraction amplitude in PNC rats. Also, tadalafil improved the amplitude of urethral relaxation during bladder contraction in PNC rats. Urethral nNOS transcript levels were upregulated in PNC rats compared to control rats. CONCLUSIONS: PNC rats revealed both DU and impaired urethral relaxation. PDE 5 inhibition in PNC rats enhanced urethral relaxation during voiding, resulting in improved voiding efficiency. Thus, urethral dysfunction could be a potential target for the treatment of inefficient voiding associated with neurogenic DU.

4-Aminopyridine attenuates muscle atrophy after sciatic nerve crush injury in mice.

INTRODUCTION: We recently demonstrated the beneficial effects of 4-aminopyridine (4-AP), a potassium channel blocker, in enhancing remyelination and recovery of nerve conduction velocity and motor function after sciatic nerve crush injury in mice. Although muscle atrophy occurs very rapidly after nerve injury, the effect of 4-AP on muscle atrophy and intrinsic muscle contractile function is largely unknown. METHODS: Mice were assigned to sciatic nerve crush injury and no-injury groups and were followed for 3, 7, and 14 days with/without 4-AP or saline treatment. Morphological, functional, and transcriptional properties of skeletal muscle were assessed. RESULTS: In addition to improving in vivo function, 4-AP significantly reduced muscle atrophy with increased muscle fiber diameter and contractile force. Reduced muscle atrophy was associated with attenuated expression of atrophy-related genes and increased expression of proliferating stem cells. DISCUSSION: These findings provide new insights into the potential therapeutic benefits of 4-AP against nerve injury-induced muscle atrophy and dysfunction. Muscle Nerve 60: 192-201, 2019.

Development of the interscutularis model as an outcome measure for facial nerve surgery.

INTRODUCTION: Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial nerve branches and autonomic innervation. The posterior auricular nerve (PAN) is an isolated branch of the facial nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial nerve palsy utilizing the PAN and interscutularis muscle. METHODS: A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), nerve excision (Ex, n = 10), or nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial nerve trunk with size 5 jeweler's forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. RESULTS: Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p < 0.05), but no significant change in right ear movement following POD05. Ex animals had a significant reduction in right ear movement at all PODs in comparison to the left ear (p < 0.05) with no significant change in right ear movement during the study period (p = 0.94). Cr animals showed a significant reduction in right ear movement compared to the left at POD01, POD10, and POD20 (p < 0.05). At POD30, there was no significant difference between ear movement on either side (p = 0.35). There was a significant change in right ear movement during the data collection period (p < 0.05). CONCLUSION: The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial nerve surgery.

Clinical Outcomes of Zone 2 Flexor Tendon Repairs Using the Modified Lim/Tsai Technique.

BACKGROUND: The single looped suture modified Lim/Tsai technique is widely used for flexor tendon repairs. It has been shown to possess better biomechanical properties and require less repair time per tendon as compared to the double looped suture original Lim/Tsai technique. However, there is no clinical data on the modified technique. METHODS: The retrospective study included zone 2 flexor tendon repairs made using the modified Lim/Tsai technique from January 2008 to December 2014. Clinical outcome was assessed using the revised Strickland and Glogovac criteria, which categorises repairs based on the total active motion of the repaired digit. RESULTS: Sixty-two patients with 74 digits were included. The overall mean total active motion was 122°. The overall satisfactory outcome of the modified Lim/Tsai technique was 81.1%. The rupture rate of the modified Lim/Tsai technique was 2.7%. Using multivariate linear regression model, we found that outcomes were negatively influenced by subzone 2C and crush/saw injuries, but not by concomitant neurovascular injuries or post-operative follow-up duration. CONCLUSIONS: Based on this retrospective study of patients with zone 2 flexor tendon injuries, the clinical outcomes of modified and original Lim/Tsai techniques are comparable. As such, there is no clinical evidence favouring one over the other.

Extracorporeal potassium binding for the management of hyperkalemia in an anephric model of crush injury.

BACKGROUND: Potassium-binding polymers have shown promising results in an anephric porcine hyperkalemia model. The benefits of the polymer in a clinically relevant injury model remain unknown. We hypothesized that potassium-binding cartridges would control serum potassium concentration in a porcine hemorrhagic shock model with supraceliac aortic occlusion and a limb crush injury. METHODS: Ten Yorkshire-cross swine were anesthetized and instrumented. Pigs underwent splenectomy and bilateral nephrectomy. Hemorrhagic shock was induced for 30 minutes while a leg compression device was applied. Pigs underwent supraceliac aortic occlusion for 60 minutes and were resuscitated with shed blood. The leg compression device was removed 20 minutes after balloon deflation. After 20 minutes of reperfusion, animals were randomized to extracorporeal circulation with (treatment) or without (control) the potassium binding cartridges. In both groups, blood was circulated through a hemodialyzer with a peristaltic pump. In the treatment group, the ultrafiltrate was diverted from the hemodialyzer through cartridges containing the polymer and returned to the extracorporeal circuit. Animals were resuscitated with 0.9% saline boluses and a norepinephrine infusion. The change in serum potassium concentration (ΔK) was calculated as serum [K]T390 - serum [K]T0. RESULTS: There was a significant difference in serum potassium concentration between groups (p < 0.001). ΔK was significantly higher in the control than the treatment group (3.75 [3.27-4.42] and 1.15 [0.62-1.59] mmol/L, respectively; p = 0.03). There were no differences in mean arterial pressure (p = 0.14), isotonic crystalloids requirement (p = 0.51), or norepinephrine dose (p = 0.83) between groups. Serum lactate concentration was significantly higher in the control group (p < 0.001). At the end of the experiment, the [K] was reduced by 25% (24.9%-27.8%) across the cartridges. CONCLUSION: The cartridges controlled serum potassium concentrations without dialysate and retained potassium binding capabilities over 4 hours. There were no deleterious effects on hemodynamic parameters. Those cartridges might be beneficial adjuncts for hyperkalemia management in austere environments. LEVEL OF EVIDENCE: Translational science study, level I.

Free vascularized osteoseptocutaneous fibular flap for radius shaft nonunion: The final solution when the iliac crest autograft fails. A case report.

Treatment of forearm nonunion associated with bone defects can be challenging. Restoring the correct length and rotation are two main principles for the management of these patients. Herein, we describe a patient with isolated radius nonunion already treated with an iliac crest autograft with no success. A free vascularized osteoseptocutaneous fibular autogenous graft was harvested as the final solution to managed long bone defect after previous multiple surgeries. At the 1- year follow-up, the patient gained full range of motion and was functioning well.

Exosomes derived from mesenchymal stem cells exert therapeutic effect in a rat model of cavernous nerves injury.

Postradical prostatectomy erectile dysfunction (pRP-ED) is a major health issue. There has been a shortage of an effective treatment method until now. In this study, a total of 48 adult male Sprague-Dawley (SD) rats were randomly equally divided into four groups, including group 1-sham surgery with cavernous nerve exposure plus vehicle, group 2-bilateral cavernous nerve injury (BCNI) plus vehicle, group 3-BCNI plus adipose-derived mesenchymal stem cells (ADSCs)-derived exosomes (ADSC-Exo), and group 4-BCNI plus bone marrow-derived mesenchymal stem cell (BMSCs)-derived exosomes (BMSC-Exo). Twenty-one days following surgery, erectile function was measured before tissue harvest. Histologic and Western blot analyses were then performed. Exosomes were capable of internalization into human umbilical vein endothelial cells (HUVEC) in vitro and could be detected in the corpus cavernosum in vivo. The nNOS expression in the penile dorsal nerves (DN) and major pelvic ganglion (MPG), protein level of neurofilament in the DN, endothelial markers vWF, alpha smooth muscle actin (α-SMA), the ratio of smooth muscle to collagen content were obviously lower in BCNI group compared with the sham group, while ADSC-Exo and BMSC-Exo groups resulted in significant restoration of the above histopathological changes. Moreover, BCNI treated with ADSC-Exo or BMSC-Exo had significantly higher mean intracavernous pressure/mean arterial pressure ratio compared with BCNI group. The results demonstrated that both ADSC-Exo and BMSC-Exo treatment could significantly alleviate pathological changes and improve the erectile function in BCNI-related rats. Exosomes derived from ADSCs and BMSCs may be a potential agent for pRP-ED treatment.

Systemic Inflammatory Response and Multiple Organ Dysfunctions Following Crush Injury: a New Experimental Model in Rabbits.

In this study, we aim to develop a new, reproducible crush injury (CI) model in rabbits. Anesthetized rabbits were compressed on both hind limbs using a special instrument for 6 h followed by 3 h of reperfusion. Blood samples and injured muscles were collected for biochemical analysis and morphological evaluation. Survival observation lasted for 72 h. Bilateral compressions with 10 kg/kg body weight (BW), but not with 5 kg/kg BW, reduced serious systemic impairment. Bilateral compressions with 10 kg/kg BW resulted in severe lactic acidosis; increased serum K+, creatine phosphokinase, aspartate transaminase, alanine transaminase, blood urea nitrogen, and creatinine levels; and a sharply decreased mean arterial blood pressure after compression release. Serious tissue edema and inflammation were observed in the damaged muscles. The mortality rates in compression groups were 20% (5 kg/kg BW) and 60% (10 kg/kg BW). There was a significant increase in plasma concentrations of TNF-α and IL-1ß after compression. Plasma IL-1ß levels returned to control levels at 6 h after compression release, whereas TNF-α peaked at 12 h following reperfusion. Furthermore, antiinflammatory cytokines, including IL-4 and IL-10, were also increased after compression, and these two cytokines peaked at 12 h after compression release. Our data suggested that bilateral compression with 10 kg/kg BW on rabbits' hind limbs is a reproducible CI model, and we also reported the CI-induced systemic inflammatory responses and changes of cytokines over time.

Possible role of antioxidative capacity of (-)-epigallocatechin-3-gallate treatment in morphological and neurobehavioral recovery after sciatic nerve crush injury.

OBJECTIVE This study examined the capacity of the major polyphenolic green tea extract (-)-epigallocatechin-3-gallate (EGCG) to suppress oxidative stress and stimulate the recovery and prompt the regeneration of sciatic nerve after crush injury. METHODS Adult male Wistar rats were randomly assigned to one of 4 groups: 1) Naïve, 2) Sham (sham injury, surgical control group), 3) Crush (sciatic nerve crush injury treated with saline), and 4) Crush+EGCG (sciatic nerve crush injury treated with intraperitoneally administered EGCG, 50 mg/kg). All animals were tested for motor and sensory neurobehavioral parameters throughout the study. Sciatic nerve and spinal cord tissues were harvested and processed for morphometric and stereological analysis. For the biochemical assays, the time points were Day 1, Day 7, Day 14, and Day 28 after nerve injury. RESULTS After sciatic nerve crush injury, the EGCG-treated animals (Crush+EGCG group) showed significantly better recovery of foot position and toe spread and 50% greater improvement in motor recovery than the saline-treated animals (Crush group). The Crush+EGCG group displayed an early hopping response at the beginning of the 3rd week postinjury. Animals in the Crush+EGCG group also showed a significant reduction in mechanical allodynia and hyperalgesia latencies and significant improvement in recovery from nociception deficits in both heat withdrawal and tail flick withdrawal latencies compared with the Crush group. In both the Crush+EGCG and Crush groups, quantitative evaluation revealed significant morphological evidence of neuroregeneration according to the following parameters: mean cross-sectional area of axons, myelin thickness in the sciatic nerve (from Week 4 to Week 8), increase of myelin basic protein concentration and gene expression in both the injured sciatic nerve and spinal cord, and fiber diameter to axon diameter ratio and myelin thickness to axon diameter ratio at Week 2 after sciatic nerve injury. However, the axon area remained much smaller in both the Crush+EGCG and Crush groups compared with the Sham and Naïve groups. The number of axons per unit area was significantly decreased in the Crush+EGCG and Crush groups compared with controls. Sciatic nerve injury produced generalized oxidative stress manifested as a significant increase of isoprostanes in the urine and decrease of the total antioxidant capacity (TAC) of the blood from Day 7 until Day 14. EGCG-treated rats showed significantly less increase of isoprostanes than saline-treated animals and also showed full recovery of TAC levels by Day 14 after nerve injury. In spinal cord tissue analysis, EGCG-treated animals showed induced glutathione reductase and suppressed induction of heme oxygenase 1 gene expression compared with nontreated animals. CONCLUSIONS EGCG treatment suppressed the crush-induced production of isoprostanes and stimulated the recovery of the TAC and was associated with remarkable alleviation of motor and sensory impairment and significant histomorphological evidence of neuronal regeneration following sciatic nerve crush injury in rats. The findings of this study suggest that EGCG can be used as an adjunctive therapeutic remedy for nerve injury. However, further investigations are needed to establish the antioxidative mechanism involved in the regenerative process after nerve injury. Only upregulation of glutathione reductase supports the idea that EGCG is acting indirectly via induction of enzymes or transcription factors.

Quercetin promotes motor and sensory function recovery following sciatic nerve-crush injury in C57BL/6J mice.

Injuries and diseases that occur in the nervous system are common and have few effective treatments. Previous studies have shown that quercetin has a therapeutic effect on nervous system injuries, but its potential effects on and mechanisms of action related to behavioral recovery and axonal regrowth have not been investigated. Here, we showed that quercetin administration promotes behavioral recovery following sciatic nerve-crush injury in mice. Long-term evaluation showed that mice administered 20 mg·kg-1·day-1 quercetin for 35 days had a greater sensorimotor recovery compared with all other treatment groups. The mechanisms behind these effects were further investigated, and quercetin was found to regulate the expression of genes involved in regeneration and trophic support. Moreover, quercetin increased cyclic adenosine monophosphate expression and downstream pathway activation, which directly leads to neuronal growth activation in peripheral axon regeneration. In addition, quercetin enhanced axon remyelination, motor nerve conduction velocity and plantar muscle function, indicating that the degree of distal portion hypotrophy during the peripheral axon regeneration process was reduced. These results suggest that quercetin accelerates functional recovery by up-regulating neuronal intrinsic growth capacity and postponing distal atrophy. Overall, quercetin triggered multiple effects to promote behavioral recovery following sciatic nerve-crush injury in mice.

Merlin controls the repair capacity of Schwann cells after injury by regulating Hippo/YAP activity.

Loss of the Merlin tumor suppressor and activation of the Hippo signaling pathway play major roles in the control of cell proliferation and tumorigenesis. We have identified completely novel roles for Merlin and the Hippo pathway effector Yes-associated protein (YAP) in the control of Schwann cell (SC) plasticity and peripheral nerve repair after injury. Injury to the peripheral nervous system (PNS) causes a dramatic shift in SC molecular phenotype and the generation of repair-competent SCs, which direct functional repair. We find that loss of Merlin in these cells causes a catastrophic failure of axonal regeneration and remyelination in the PNS. This effect is mediated by activation of YAP expression in Merlin-null SCs, and loss of YAP restores axonal regrowth and functional repair. This work identifies new mechanisms that control the regenerative potential of SCs and gives new insight into understanding the correct control of functional nerve repair in the PNS.

Neural Progenitor-Like Cells Induced from Human Gingiva-Derived Mesenchymal Stem Cells Regulate Myelination of Schwann Cells in Rat Sciatic Nerve Regeneration.

Regeneration of peripheral nerve injury remains a major clinical challenge. Recently, mesenchymal stem cells (MSCs) have been considered as potential candidates for peripheral nerve regeneration; however, the underlying mechanisms remain elusive. Here, we show that human gingiva-derived MSCs (GMSCs) could be directly induced into multipotent NPCs (iNPCs) under minimally manipulated conditions without the introduction of exogenous genes. Using a crush-injury model of rat sciatic nerve, we demonstrate that GMSCs transplanted to the injury site could differentiate into neuronal cells, whereas iNPCs could differentiate into both neuronal and Schwann cells. After crush injury, iNPCs, compared with GMSCs, displayed superior therapeutic effects on axonal regeneration at both the injury site and the distal segment of the injured sciatic nerve. Mechanistically, transplantation of GMSCs, especially iNPCs, significantly attenuated injury-triggered increase in the expression of c-Jun, a transcription factor that functions as a major negative regulator of myelination and plays a central role in dedifferentiation/reprogramming of Schwann cells into a progenitor-like state. Meanwhile, our results also demonstrate that transplantation of GMSCs and iNPCs consistently increased the expression of Krox-20/EGR2, a transcription factor that governs the expression of myelin proteins and facilitates myelination. Altogether, our findings suggest that transplantation of GMSCs and iNPCs promotes peripheral nerve repair/regeneration, possibly by promoting remyelination of Schwann cells mediated via the regulation of the antagonistic myelination regulators, c-Jun and Krox-20/EGR2. Stem Cells Translational Medicine 2017;6:458-470.

Systemic Transplantation of Bone Marrow Mononuclear Cells Promotes Axonal Regeneration and Analgesia in a Model of Wallerian Degeneration.

BACKGROUND: Reinnervation timing after nerve injury is critical for favorable axonal regeneration, remyelination, and clinical improvement. Considering bone marrow mononuclear cells (BMMC) are easily obtained and readily available for transplant, this work analyzed the effect of BMMC systemic administration on nerve repair and pain behavior. METHODS: Adult rats with sciatic nerve crush were immediately and systemically injected BMMC through the caudal artery. Nontreated, sham and naïve rats were also included. Histological, immunohistochemical, biochemical, functional, and behavioral analyses were performed in nerves harvested from each group at different survival times. RESULTS: Axons in BMMC-treated rats exhibited a more conserved morphological appearance than those in nontreated rats, as observed at different survival times both in semithin sections and ultrastructural analysis. BMMC-treated rats also showed a reduction in major myelin protein immunoreactive clusters 7 and 14 days postinjury, as compared with nontreated rats. Electrophysiological analysis showed BMMC treatment to slightly improve the amplitude of compound muscle action potential starting at 14 days postinjury. Finally, mechanical withdrawal threshold revealed a full preventive action against transient mechanical hypersensitivity in BMMC-treated rats. CONCLUSIONS: These data demonstrate the efficiency of BMMC, systemically and noninvasively transplanted, in correcting morphological, functional and behavioral alterations resulting from peripheral nerve injury.

Sesame oil improves functional recovery by attenuating nerve oxidative stress in a mouse model of acute peripheral nerve injury: role of Nrf-2.

Peripheral nervous injury (PNI) is a common form of trauma in modern society, especially in sport players. Despite the advance of therapy for PNI, the recovery of function can never reach the preinjury level after treatments. Recently, inhibiting neural oxidative stress shows a beneficial effect in improving functional recovery after PNI. In addition, sesame oil has been reported to possess the excellent antioxidative properties. However, whether sesame oil can improve the functional recovery after PNI by its antioxidative effect has never been investigated. Thirty mice were randomly divided into five groups of six: group I mice received sham operation; group II mice received sciatic nerve crush; and groups III-V mice daily ingested 0.5, 1 and 2 ml/kg of sesame oil for 6 days, respectively, after sciatic nerve crush. Oxidative stress, GAP43 and nuclear Nrf2 levels as well as spinal somatosensory evoked potentials were assessed on day 6, while paw withdrawal latency and sciatic function index were assessed on days 0, 3, and 6. Sesame oil significantly decreased lipid peroxidation and increased nuclear factor erythroid 2-related factor 2 and GAP43 expression in sciatic nerve. Furthermore, sesame oil improved electrophysiological and functional assessments in mice with sciatic nerve crush. In conclusion, sesame oil may improve nerve functional recovery by attenuating nerve oxidative stress in mouse acute peripheral nerve injury. Further, application of natural product sesame oil may be an alternative approach for improving nerve functional recovery in the clinical setting.

Synaptic plasticity in the facial nucleus in rats following infraorbital nerve manipulation after facial nerve injury.

The aim of this study is to investigate the effect of sensory input on the neural plasticity in the facial nucleus following facial nerve injury. Adult male Wistar rats were randomly assigned to four groups: (1) sham control; (2) facial nerve crush (FNC); (3) nerve crush plus daily manual vibrissal stimulation (FMS); and (4) nerve crush with infraorbital nerve transection plus daily manual stimulation (FIMS). Plasticity related proteins in the facial nucleus were evaluated by western blot at 7, 14, and 28 days postsurgery (n = 6/group per timepoint). Synaptophysin-positive terminals were evaluated by immunohistochemistry in a second set of animals (n = 6/group) at 14 days. Quantitation of synaptophysin immunostaining showed that rats in the FNC group had a significantly lower mean number of pixels compared to control animals (29.1 ± 2.6 × 10(6) vs. 34.2 ± 2.3 × 10(6); P < 0.05). Values in the FMS group (33.2 ± 1.7 × 10(6)) were similar to that of the control group, while the mean number in the FIMS group (26.5 ± 2.4 × 10(6)) was significantly lower than in the control group. Synapsin I phosphorylation was reduced to 70-83 % in FNC rats, but increased to 121-132 % in the FMS group (P < 0.05 vs. controls). Phosphorylation of cAMP response element-binding protein was similarly reduced by facial nerve crush, which was delayed in FMS animals (P < 0.05 vs. controls at 28 days). Expression and phosphorylation of all proteins were reduced to the lowest in the FIMS group (all P < 0.05). Sensory input from the IoN have a strong effect on synaptic plasticity within the facial nucleus, which is necessary to achieve the benefit of manual stimulation.

Sciatic nerve regeneration in rats subjected to ketogenic diet.

OBJECTIVES: Ketogenic diet (KD) is a high-fat-content diet with insufficiency of carbohydrates that induces ketogenesis. Besides its anticonvulsant properties, many studies have shown its neuroprotective effect in central nervous system, but its influence on peripheral nervous system has not been studied yet. We examined the influence of KD on regeneration of peripheral nerves in adult rats. METHODS: Fifty one rats were divided into three experimental (n = 15) and one control (n = 6) groups. Right sciatic nerve was crushed and animals were kept on standard (ST group) or ketogenic diet, the latter was introduced 3 weeks before (KDB group) or on the day of surgery (KDA group). Functional (CatWalk) tests were performed once a week, and morphometric (fiber density, axon diameter, and myelin thickness) analysis of the nerves was made after 6 weeks. Body weight and blood ketone bodies level were estimated at the beginning and the end of experiment. RESULTS: Functional analysis showed no differences between groups. Morphometric evaluation showed most similarities to the healthy (uncrushed) nerves in KDB group. Nerves in ST group differed mostly from all other groups. Ketone bodies were elevated in both KD groups, while post-surgery animals' body weight was lower as compared to ST group. DISCUSSION: Regeneration of sciatic nerves was improved in KD - preconditioned rats. These results suggest a neuroprotective effect of KD on peripheral nerves.