Short-Duration, Pulsatile, Electrical Stimulation Therapy Accelerates Axon Regeneration and Recovery following Tibial Nerve Injury and Repair in Rats.

BACKGROUND: Repair of nerve injuries can fail to achieve adequate functional recovery. Electrical stimulation applied at the time of nerve repair can accelerate axon regeneration, which may improve the likelihood of recovery. However, widespread use of electrical stimulation may be limited by treatment protocols that increase operative time and complexity. This study evaluated whether a short-duration electrical stimulation protocol (10 minutes) was efficacious to enhance regeneration following nerve repair using rat models. METHODS: Lewis and Thy1-green fluorescent protein rats were randomized to three groups: 0 minutes of electrical stimulation (no electrical stimulation; control), 10 minutes of electrical stimulation, and 60 minutes of electrical stimulation. All groups underwent tibial nerve transection and repair. In the intervention groups, electrical stimulation was delivered after nerve repair. Outcomes were assessed using immunohistochemistry, histology, and serial walking track analysis. RESULTS: Two weeks after nerve repair, Thy1-green fluorescent protein rats demonstrated increased green fluorescent protein-positive axon outgrowth from the repair site with electrical stimulation compared to no electrical stimulation. Serial measurement of walking tracks after nerve repair revealed recovery was achieved more rapidly in both electrical stimulation groups as compared to no electrical stimulation. Histologic analysis of nerve distal to the repair at 8 weeks revealed robust axon regeneration in all groups. CONCLUSIONS: As little as 10 minutes of intraoperative electrical stimulation therapy increased early axon regeneration and facilitated functional recovery following nerve transection with repair. Also, as early axon outgrowth increased following electrical stimulation with nerve repair, these findings suggest electrical stimulation facilitated recovery because of earlier axon growth across the suture-repaired site into the distal nerve to reach end-organ targets. CLINICAL RELEVANCE STATEMENT: Brief (10-minute) electrical stimulation therapy can provide similar benefits to the 60-minute protocol in an acute sciatic nerve transection/repair rat model and merit further studies, as they represent a translational advantage.

[Selective ultrasound-guided hydrodissection of gastrocnemius nerve branch after post-surgical entrapment: Apropos of a case]. / Hidrodisección ecoguiada selectiva de rama nerviosa gemelar tras atrapamiento posquirúrgico: a propósito de un caso.

Chronic or recalcitrant plantar fasciitis is a cause of persistent plantar pain. These cases are usually resistant to conventional treatments consisting of exercises, orthoses, shock waves and infiltrations and require a surgical approach. Proximal medial gastrocnemius release is a surgical option that provides satisfactory results, but is not free of complications, which include injuries and nerve entrapment. We report the first published case of symptomatic medial gastrocnemius branch entrapment in the post-surgical scar of a tenotomy for the treatment of recalcitrant plantar fasciitis. We propose ultrasound-guided hydrodissection with local anesthetic as a treatment with promising results.

Musculoskeletal ultrasonography combined with electromyography in the diagnosis of massage-inducted lateral plantar nerve injury: A case report.

INTRODUCTION: It is well known that foot massage is a very prevalent stress relief method in China. Literatures have reported various massage-inducted peripheral nerve injuries. However, massage-inducted lateral plantar nerve (LPN) injury is very rare. Here, we represent an unusual case of massage-inducted LPN damage, and we also report the diagnostic method of this patient using musculoskeletal ultrasonography combined with electromyography (EMG). PATIENT CONCERNS: A 21-year-old woman presented symptoms of redness, swelling, pain and numbness in the medial right ankle joint for 2 days. DIAGNOSIS: The results of musculoskeletal ultrasonography and EMG provide great help for doctors to make accurate diagnosis. The patient was eventually diagnosed with LPN injury. INTERVENTIONS: No further foot massage was allowed. Vitamin B12 was taken orally for 2 months. Conservative therapy, including electrical stimulation therapy and infrared therapy, was conducted. Besides, active rehabilitation training was also performed. OUTCOMES: The discomfort symptoms were relieved significantly after 2 months conservative treatment. Clinical symptoms and EMG examination illustrated satisfactory result during follow up time. CONCLUSION: The report showed that the masseur should be very careful when doing foot massage to prevent nerve damage. Besides, musculoskeletal ultrasonography combined with EMG can provide important evidence for accurate and effective diagnosis of LPN injury.

Isolated injury to the tibial division of sciatic nerve after self-massage of the gluteal muscle with massage ball: A case report.

INTRODUCTION: An isolated injury to the tibial division is rare among compressive sciatic neuropathy. To date, isolated injury to the tibial division of the sciatic nerve after self-massage of the gluteal muscle has not been reported. Here, we report a case of compressive sciatic neuropathy diagnosed after self-massage of the gluteal muscle using magnetic resonance image (MRI) and ultrasound images and its associated therapeutic process. PATIENT CONCERNS: A 50-year-old woman presented right lower extremity pain for the past 7 days. DIAGNOSIS: Electrophysiological findings were consistent with right tibial neuropathy proximal to the branch to hamstring muscles. However, T2-weighted MRI showed high signal intensity and swelling in the right sciatic nerves from the superior gemellus level to the quadratus femoris level. After considering both radiologic and electrophysiological findings, the patient was diagnosed with an isolated injury to the tibial division of the right sciatic nerve. INTERVENTIONS: The patient agreed to an ultrasound-guided perineural steroid injection upon receiving detailed explanation of the procedure. OUTCOMES: After the injection, there was significant improvement in pain. CONCLUSION: Therefore, in making a diagnosis of sciatic neuropathy, it may be important to find the lesion via MRI than relying solely on the patient's history or electrophysiologic study.

Electrical muscle stimulation elevates intramuscular BDNF and GDNF mRNA following peripheral nerve injury and repair in rats.

Despite advances in surgery, patients with nerve injuries frequently have functional deficits. We previously demonstrated in a rat model that daily electrical muscle stimulation (EMS) following peripheral nerve injury and repair enhances reinnervation, detectable as early as two weeks post-injury. In this study, we explain the enhanced early reinnervation observed with electrical stimulation. In two groups of rats, the tibial nerve was transected and immediately repaired. Gastrocnemius muscles were implanted with intramuscular electrodes for sham or muscle stimulation. Muscles were stimulated daily, eliciting 600 contractions for one hour/day, repeated five days per week. Sixteen days following nerve injury, muscles were assessed for functional reinnervation by motor unit number estimation methods using electromyographic recording. In a separate cohort of rats, surgical and electrical stimulation procedures were identical but muscles and distal nerve stumps were harvested for molecular analysis. We observed that stimulated muscles had significantly higher motor unit number counts. Intramuscular levels of brain-derived and glial cell line-derived neurotrophic factor (BDNF and GDNF) mRNA were significantly upregulated in muscles that underwent daily electrical stimulation compared to those without stimulation. The corresponding levels of trophic factor mRNA within the distal stump were not different from one another, indicating that the intramuscular electrical stimulus does not modulate Schwann cell-derived trophic factor transcription. Stimulation over a three-month period maintained elevated muscle-derived GDNF but not BDNF mRNA. In conclusion, EMS elevates intramuscular trophic factor mRNA levels which may explain how EMS enhances neural regeneration following nerve injury.

Activity-dependent degeneration of axotomized neuromuscular synapses in Wld S mice.

Activity and disuse of synapses are thought to influence progression of several neurodegenerative diseases in which synaptic degeneration is an early sign. Here we tested whether stimulation or disuse renders neuromuscular synapses more or less vulnerable to degeneration, using axotomy as a robust trigger. We took advantage of the slow synaptic degeneration phenotype of axotomized neuromuscular junctions in flexor digitorum brevis (FDB) and deep lumbrical (DL) muscles of Wallerian degeneration-Slow (Wld(S)) mutant mice. First, we maintained ex vivo FDB and DL nerve-muscle explants at 32°C for up to 48 h. About 90% of fibers from Wld(S) mice remained innervated, compared with about 36% in wild-type muscles at the 24-h checkpoint. Periodic high-frequency nerve stimulation (100 Hz: 1s/100s) reduced synaptic protection in Wld(S) preparations by about 50%. This effect was abolished in reduced Ca(2+) solutions. Next, we assayed FDB and DL innervation after 7 days of complete tetrodotoxin (TTX)-block of sciatic nerve conduction in vivo, followed by tibial nerve axotomy. Five days later, only about 9% of motor endplates remained innervated in the paralyzed muscles, compared with about 50% in 5 day-axotomized muscles from saline-control-treated Wld(S) mice with no conditioning nerve block. Finally, we gave mice access to running wheels for up to 4 weeks prior to axotomy. Surprisingly, exercising Wld(S) mice ad libitum for 4 weeks increased about twofold the amount of subsequent axotomy-induced synaptic degeneration. Together, the data suggest that vulnerability of mature neuromuscular synapses to axotomy, a potent neurodegenerative trigger, may be enhanced bimodally, either by disuse or by hyperactivity.

Effects of intraperitoneally administered folic acid on the healing of repaired tibial nerves in rats.

BACKGROUND: Complete nerve regeneration and clinical healing remain a challenge despite considerable advances in the treatment of peripheral nerve injuries. To improve nerve regeneration, several experimental molecular procedures have been attempted. This study aimed to investigate the effects of folic acid on peripheral nerve healing after transection and end-to-end suture repair of the tibial nerve in rats. METHODS: In this study, 20 adult male Wistar Albino rats weighing 225 to 250 g were used. The right tibial nerves of 20 rats were explored, transected, and sutured using the end-to-end technique. The rats were randomly allocated to either the intraperitoneally administered folic acid group (test group) or the control group. Preoperative and 6-week postoperative neurophysiological studies were performed by the same researcher. Myelin-sheathed axons were counted. RESULTS: The results demonstrated that the folic acid-treated group exhibited improved electromyographic results compared with the control group. Histological evaluation revealed that the axons were well preserved and that the axon quantity and density were increased in the test group compared with the control group. Quantitative results also increased in the test group compared with the control group (p = 0.001). CONCLUSION: In this study, 6-week intraperitoneal administration of 80 µg/kg of folic acid significantly improved peripheral nerve healing. Histological analysis of the group that received folic acid revealed increased axon myelination with little granular tissue or fibrosis. We propose that folic acid supplementation may be an effective component of peripheral nerve injury treatment.

Effect of vitamin B12 on functional recovery and histopathologic changes of tibial nerve-crushed rats.

Recent studies have suggested a neuroprotective effect for vitamin B12. The present study investigated the effects of vitamin B12, diclofenac and celecoxib in separate and combined treatments on functional recovery of crushed tibial nerve in rats. In ketamine plus xylazin anesthetized rats, right tibial nerve was crushed using a small hemoatatic forceps. Footprints were recorded 1 day before and on days 7, 14 and 21 after induction of nerve injury. Tibial functional index (TFI) was used to evaluate the recovery of tibial nerve function. Histological changes of tibial nerve were investigated by light microscopy. The recovery of TFI values were significantly accelerated with 10 consecutive days treatments with 0.1 and 0.5 mg/kg of vitamin B12, 5 mg/kg of diclofenac and 1 and 5 mg/kg of celecoxib. The severity of Wallerian degeneration was reduced by above-mentioned doses of vitamin B12, diclofenac and celecoxib. Documented effects were observed when 0.1 mg/kg of vitamin B12 was concurrently used with 1 mg/kg of diclofenac and or 0.2 mg/kg of celecoxib. In the present study, vitamin B12, celecoxib and diclofenac (at a high dose) showed neuroprotective effects. Inhibition of cyclooxygenase (COX) 1 and 2 pathways may be involved in neuroprotective effect of vitamin B12.

Enhancement of peripheral nerve regeneration due to treadmill training and electrical stimulation is dependent on androgen receptor signaling.

Moderate exercise in the form of treadmill training and brief electrical nerve stimulation both enhance axon regeneration after peripheral nerve injury. Different regimens of exercise are required to enhance axon regeneration in male and female mice (Wood et al.: Dev Neurobiol 72 (2012) 688-698), and androgens are suspected to be involved. We treated mice with the androgen receptor blocker, flutamide, during either exercise or electrical stimulation, to evaluate the role of androgen receptor signaling in these activity-based methods of enhancing axon regeneration. The common fibular (CF) and tibial (TIB) nerves of thy-1-YFP-H mice, in which axons in peripheral nerves are marked by yellow fluorescent protein (YFP), were transected and repaired using CF and TIB nerve grafts harvested from non-fluorescent donor mice. Silastic capsules filled with flutamide were implanted subcutaneously to release the drug continuously. Exercised mice were treadmill trained 5 days/week for 2 weeks, starting on the third day post-transection. For electrical stimulation, the sciatic nerve was stimulated continuously for 1 h prior to nerve transection. After 2 weeks, lengths of YFP+ profiles of regenerating axons were measured from harvested nerves. Both exercise and electrical stimulation enhanced axon regeneration, but this enhancement was blocked completely by flutamide treatments. Signaling through androgen receptors is necessary for the enhancing effects of treadmill exercise or electrical stimulation on axon regeneration in cut peripheral nerves.

The influence of spatial pulsed magnetic field application on neuropathic pain after tibial nerve transection in rat.

The purpose of the study was to examine the influence of the spatial variable magnetic field (induction: 150-300 µT, 80-150 µT, 20-80 µT; frequency 40 Hz) on neuropathic pain after tibial nerve transection. The experiments were carried out on 64 male Wistar C rats. The exposure of animals to magnetic field was performed 1 d/20 min., 5 d/week, for 28 d. Behavioural tests assessing the intensity of allodynia and sensitivity to mechanical and thermal stimuli were conducted 1 d prior to surgery and 3, 7, 14, 21 and 28 d after the surgery. The extent of autotomy was examined. Histological and immunohistochemical analysis was performed. The use of extremely low-frequency magnetic fields of minimal induction values (20-80 µT/40 Hz) decreased pain in rats after nerve transection. The nociceptive sensitivity of healthy rats was not changed following the exposition to the spatial magnetic field of the low frequency. The results of histological and immunohistochemical investigations confirm those findings. Our results indicate that extremely low-frequency magnetic field may be useful in the neuropathic pain therapy.

Attenuating effect of standardized fruit extract of Punica granatum L in rat model of tibial and sural nerve transection induced neuropathic pain.

BACKGROUND: Injury to a nerve is the most common reason of acquired peripheral neuropathy. Therefore, searching for effective substance to recover of nerve after injury is need of present era. The current study investigates the protective potential of Standardized Fruit Extract of Punica granatum L (PFE) [Ellagic acid (41.6%), Punicalagins (10%), Granatin (5.1%)] in Tibial & Sural Nerve Transection (TST) induced neuropathic pain in rats. METHODS: TST was performed by sectioning tibial and sural nerve portions of the sciatic nerve and leaving the common peroneal nerve intact. Acetone drop, pin-prick, hot plate, paint brush & Walking Track tests were performed to assess cold allodynia; mechanical heat, hyperalgesia and dynamic mechanical allodynia & tibial functional index respectively. The levels of TNF-α, TBARS, GSH and Nitrite were measured in the sciatic nerve as an index of inflammation & oxidative stress. RESULTS: TST led to significant development of cold allodynia; mechanical and heat hyperalgesia; dynamic mechanical allodynia; functional deficit in walking along with rise in the levels of TBARS, TNF-α, GSH and Nitrite. Administrations of PFE (100 & 300 mg/kg oral), significantly attenuate TST induced behavioral & biochemical changes. Pretreatments of BADGE (120 mg/kg IP) a PPAR-γ antagonist and nitric oxide precursor L-arginine (100 mg/kg IP) abolished the protective effect of PFE. Whereas, pretreatment of L-NAME (5 mg/kg IP) a NOS inhibitor significantly potentiated PFE's protective effect of PFE. CONCLUSION: PFE shown to have attenuating effect in TST induced neuropathic pain which may be attributed to potential PPAR-gamma agonistic activity, nitric oxide inhibitory, anti-inflammatory and anti oxidative actions.

Spontaneous burrowing behaviour in the rat is reduced by peripheral nerve injury or inflammation associated pain.

Pain influences many aspects of daily living and effective analgesics should reinstate normal spontaneous daily behaviours. Experiments are described herein which show that the innate, spontaneous behaviour of burrowing by rats, which can be simply and objectively assessed by measuring the amount of gravel left in a hollow tube 1 h after presentation to the rat, is reduced by peripheral nerve injury (tibial nerve transection (TNT), L5 spinal nerve transection (SNT) and partial sciatic nerve ligation (PSNL)) and also following inflammation induced by intra-plantar injection of Complete Freund's Adjuvant (CFA). Gabapentin (100 mg/kg sc) but not at 30 mg/kg sc significantly reduced burrowing activity in naive rats. All peripheral nerve injuries and CFA reduced burrowing compared with shams and rats naive to surgery. The level of mechanical hypersensitivity in rats with peripheral nerve injury did not correlate with the deficit in burrowing indicating that different parameters of the holistic pain experience are measured in these paradigms. Gabapentin at 30 mg/kg sc, but not 100 mg/kg sc, reversed the deficit in burrowing induced by TNT and ibuprofen (30 mg/kg sc) reversed the effect of CFA on burrowing. These experiments show that measurement of burrowing is a simple, objective assay of innate rodent behaviour affected by pain that is ethologically relevant to the rat, does not rely wholly on evoking a reflex and can dissociate a selective analgesic dose of gabapentin from one inducing motor impairment in the same animal.

Effect of hydroalcoholic extract of Acorus calamus on tibial and sural nerve transection-induced painful neuropathy in rats.

This study was designed to investigate the therapeutic potential of hydroalcoholic extracts of Acorus calamus (AC) in tibial and sural nerve transection (TST)-induced neuropathic pain in rats. The hot plate, paw heat allodynia, acetone drop, and pinprick tests were performed to assess the degree of heat hyperalgesia, heat and cold allodynia, and mechanical hyperalgesia, respectively, at different time intervals, i.e., day 0, 1, 3, 6, 9, 12, 15, 18, and 21. The tissue superoxide anion and total calcium were measured as markers of oxidative stress. Tissue myeloperoxidase activity was measured as a specific marker of inflammation. Histopathological evaluation was also performed in the nervous tissue to assess the axonal degeneration. Pregabalin served as positive control in this study. TST in rats significantly induced thermal hyperalgesia and allodynia, mechanical hyperalgesia, and increased the levels of superoxide anion, total calcium, and myeloperoxidase (MPO) activity. Moreover significant histological changes were also observed. Oral administration of AC hydroalcoholic extract (100 and 200 mg/kg for 14 days) attenuated TST-induced behavioral, biochemical, and histological changes. Acorus calamus has ameliorative potential in TST-induced painful neuropathy, and this effect may be attributed to its multiple actions including anti-inflammatory, antioxidant, and neuroprotective actions.

Stimulation of the medial plantar nerve for complex regional pain syndrome.

We describe a 47-year old male with complex regional pain syndrome II in the distribution of the medial plantar nerve following metatarsal fracture, which was treated with peripheral nerve stimulation. Using a new technique of nerve stimulation with a percutaneous-type electrode, the patient experienced sustained relief at 12 months follow-up. To our knowledge, this is the first report of peripheral neurostimulation effectively managing pain for the medial plantar nerve.

Acute electroacupuncture inhibits nitric oxide synthase expression in the spinal cord of neuropathic rats.

OBJECTIVES: To examine the effects of electroacupuncture stimulation on behavioral changes and neuronal nitric oxide synthase expression in the rat spinal cord after nerve injury. METHODS: Under pentobarbital anesthesia, male Sprague-Dawley rats were subjected to neuropathic surgery by tightly ligating and cutting the left tibial and sural nerves. Behavioral responses to mechanical stimulation were tested for 2 weeks post-operatively. At the end of behavioral testing, electroacupuncture stimulation was applied to ST36 (Choksamni) and SP9 (Eumleungcheon) acupoints. Immunocytochemical staining was performed to investigate changes in the expression of neuronal nitric oxide synthase-immunoreactive neurons in the L4-5 spinal cord. RESULTS: Mechanical allodynia was observed by nerve injury. The mechanical allodynia was decreased after electroacupuncture stimulation. Neuronal nitric oxide synthase expression was also decreased in L4-5 spinal cord by electroacupuncture treatment. DISCUSSION: These results suggest that electroacupuncture relieves mechanical allodynia in the neuropathic rats possibly by the inhibition of neuronal nitric oxide synthase expression in the spinal cord.

[Electroacupuncture promotes the regeneration of different fibers in rat's tibial nerve].

METHODS: 45 rats (150-200g) were divided into 9 groups. The experimental steps as follows: (1) injured left tibial nerve (group 1-8) and sham operation (group 9); (2) three days after operation, group 1, 3, 5 and 7 were stimulated with electro-acupuncture (EA) in Huantiao (+) and Sanyinjiao (-); (3) according to different survival time (group 1, 2/10 days, group 3, 4/15 days, group 5, 6/20 days, group 7, 8, 9/25 days), 48h before sacrifice, the left femoral nerve was cut, HRP was injected into the hypodermis of paw pad and gastrocnemius; (4) observe HRP labelled cells in the lumber sympathetic ganglia, ganglion spinale (L4-6) and cornu ventrale of spinal cord (L3-S3). RESULTS: EA 7 days, 2-5 labeled cells were only found in ganglion spinales of group 1; EA for 12 days, the more HRP labeled cells were observed in the lumber sympathetic ganglions (mean = 2.6), ganglion spinales (mean = 4.8) and cornu ventrale (mean = 6) of group 3 as compared with group 4 (P < 0.05); 25 days after operation, the quantity of labeled cells in group 8 was close to group 9. CONCLUSION: (1) EA promote the regeneration of three or more kinds of fibers in tibial nerve; (2) The regeneration velocity of sensory fibers was faster than sympathetic and somatic efferent fibers.