Three-dimensional motion analysis for comprehensive understanding of gait characteristics after sciatic nerve lesion in rodents

Muscle Grafts with Doxorubicin Pretreatment Produce "Empty Tubes" in the Basal Laminae, Promote Contentious Maturation of the Regenerated Axons, and Bridge 20-mm Sciatic Nerve Defects in Rats

BACKGROUND

 We newly developed a muscle graft that employs a doxorubicin pretreatment technique. The aims of this study were to reveal the biological and morphological features of the muscle tissue in the second week (Study I), to reveal the regeneration outcomes of functional and kinematic assessments of longer-term follow-up (16 weeks, Study II), and to make assessments of the muscle graft with doxorubicin pretreatment in the critical-sized nerve defect model (20 mm, Study III).

METHODS

 A total of 26 adult rats were used in this study. Doxorubicin treatment was accomplished by immersion in a doxorubicin solution for 10 minutes followed by a rinsing procedure. The rats were divided into three groups: the muscle graft with and without doxorubicin pretreatment (M-graft-w-Dox and M-graft-w/o-Dox) groups and the autologous nerve graft (N-graft) group. Assays of apoptosis, immunofluorescent histochemistry including CD68 (macrophage marker), scanning electron microscopy (SEM), morphometrical studies of the regenerated axons, nerve conduction studies, and kinematic studies were performed.

RESULTS

 The M-graft-w-Dox group contained significantly larger numbers of apoptotic cells and CD68-positive cells. SEM revealed the existence of the basal lamina, so called "empty tubes," in the M-graft-w-Dox group. Study II showed contentious maturation of the regenerated axons, especially in the compound muscle action potentials. Study III showed that even at 20 mm, the M-graft-w-Dox group promoted axonal regeneration and functional regeneration.

CONCLUSION

 The M-graft-w-Dox group showed superior regeneration results, and this easy and short-term procedure can expand the muscle graft clinical indication for the treatment of peripheral nerve defects.

Recovering the regenerative potential in chronically injured nerves by using conditioning electrical stimulation

OBJECTIVE

Chronically injured nerves pose a significant clinical challenge despite surgical management. There is no clinically feasible perioperative technique to upregulate a proregenerative environment in a chronic nerve injury. Conditioning electrical stimulation (CES) significantly improves sensorimotor recovery following acute nerve injury to the tibial and common fibular nerves. The authors' objective was to determine if CES could foster a proregenerative environment following chronically injured nerve reconstruction.

METHODS

The tibial nerve of 60 Sprague Dawley rats was cut, and the proximal ends were inserted into the hamstring muscles to prevent spontaneous reinnervation. Eleven weeks postinjury, these chronically injured animals were randomized, and half were treated with CES proximal to the tibial nerve cut site. Three days later, 24 animals were killed to evaluate the effects of CES on the expression of regeneration-associated genes at the cell body (n = 18) and Schwann cell proliferation (n = 6). In the remaining animals, the tibial nerve defect was reconstructed using a 10-mm isograft. Length of nerve regeneration was assessed 3 weeks postgrafting (n = 16), and functional recovery was evaluated weekly between 7 and 19 weeks of regeneration (n = 20).

RESULTS

Three weeks after nerve isograft surgery, tibial nerves treated with CES prior to grafting had a significantly longer length of nerve regeneration (p < 0.01). Von Frey analysis identified improved sensory recovery among animals treated with CES (p < 0.01). Motor reinnervation, assessed by kinetics, kinematics, and skilled motor tasks, showed significant recovery (p < 0.05 to p < 0.001). These findings were supported by immunohistochemical quantification of motor endplate reinnervation (p < 0.05). Mechanisms to support the role of CES in reinvigorating the regenerative response were assessed, and it was demonstrated that CES increased the proliferation of Schwann cells in chronically injured nerves (p < 0.05). Furthermore, CES upregulated regeneration-associated gene expression to increase growth-associated protein-43 (GAP-43), phosphorylated cAMP response element binding protein (pCREB) at the neuronal cell bodies, and upregulated glial fibrillary acidic protein expression in the surrounding satellite glial cells (p < 0.05 to p < 0.001).

CONCLUSIONS

Regeneration following chronic axotomy is impaired due to downregulation of the proregenerative environment generated following nerve injury. CES delivered to a chronically injured nerve influences the cell body and the nerve to re-upregulate an environment that accelerates axon regeneration, resulting in significant improvements in sensory and motor functional recovery. Percutaneous CES may be a preoperative strategy to significantly improve outcomes for patients undergoing delayed nerve reconstruction.

Improvement of Walking Analysis using the Sciatic Function Index for Sciatic Nerve Function in Injured Rat Model Treated with Low-Intensity Aerobics

BACKGROUND: Sciatica is a disease of the peripheral nerves. Sciatica indicates that there is damage to the peripheral nerves in the sciatic nerves. Factors that can affect this disease include gender, posture, parity, age, genetic factors, and occupation. Some of the pathophysiological conditions of sciatica include the pathology of the intervertebral disc, dorsal root, and sciatic nerve itself. The results of standard therapy with surgery have not been effective and very expensive. Therefore, research on therapy in sciatica cases still needs to be done and evaluated. Physical exercise treatment (aerobic] is necessary for this therapy in sciatica cases due to promote the function of peripheral nerves. AIM: This study aimed to determine the effect of aerobic exercise treatment on peripheral nerve injury and its relationship to walking function during injury-induced peripheral nerve regeneration. METHODS: This study was an experimental study with a post-test. he study sample consisted of Male Sprague-Dawley rats with an age of about 2-3 months divided into three groups. Control group was conducted by surgery without clamping/injuring the peripheral nerves. The treatment for second group (P1) was clamping/injury of peripheral nerve and given the treatment of physical exercise with aerobics. The treatment for third group (P2) was clamping/injury of peripheral nerve and not given the treatment of physical exercise with aerobics. The intensity of giving physical exercise treatment with aerobic that is carried out is for 42 days. Nerve functional evaluation was carried out using the sciatic function index (SFI) method. Histological staining for sciatic was used hematoxylin-Eosin (HE) staining and immunohistochemistry with Growth Associated Protein 43 (GAP43) [Bioss, bs-0154R] and S100 antibody [ab52642]. This research was  approved by Animal  Ethics Committee of University of Indonesia protocol (No.19-07-0852). RESULTS: There was a significant change between the 7th and 14th days (p<0.001; paired t-test) in the P1 treatment. Improvement in nerve function was found on the 14th day after being given aerobic treatment. This is indicated by the data average change in SFI scores on days 7 and 4 was from -144 to 34. This data is also supported by footprint changes for injured hindfoot data. CONCLUSION: Low intensity aerobics treatment improve the walking function and nerve function in sciatic nerve injury on day 14. This is due to the effect of physical exercise on the injured sciatic nerve.

Peripheral Nerve Basic Science Research-What Is Important for Hand Surgeons to Know?

Peripheral nerve injury and regeneration continue to be extensively studied through basic science research using animal models. A translational gap remains between basic science research and clinical application. The importance of peripheral nerve regeneration in basic science research depends on the design of the study, the outcome measures, and the time of regeneration selected. The purpose of this article is to provide an overview of the importance of the design and outcome measures of peripheral nerve basic science research, for hand surgeons to understand for potential clinical translation.

Low-Intensity Pulsed Ultrasound Prompts Both Functional and Histologic Improvements While Upregulating the Brain-Derived Neurotrophic Factor Expression after Sciatic Crush Injury in Rats

The aim of this study was to determine that low-intensity pulsed ultrasound (LIPUS) at an intensity of 140 mW/cm² promotes functional and histologic improvements in sciatic nerve crush injury in a rat model and to investigate changes over time in relevant growth factors and receptors, exploring the mechanism of LIPUS in the recovery process after injury. Toe angle in the toe-off phase, regenerative axonal length, myelinated nerve fiber density, diameter of myelinated nerve fiber, axon diameter and myelin sheath thickness were significantly higher in the LIPUS group than in the sham group. Gene and protein expression of brain-derived neurotrophic factor (BDNF) was upregulated in the LIPUS group. In conclusion, LIPUS contributed to rapid functional and histologic improvement and upregulated BDNF expression after sciatic nerve crush injury in rats.

Pro-angiogenic scaffold-free Bio three-dimensional conduit developed from human induced pluripotent stem cell-derived mesenchymal stem cells promotes peripheral nerve regeneration

Although autologous nerve grafting is widely accepted as the gold standard treatment for segmental nerve defects, harvesting autologous nerves is highly invasive and leads to functional loss of the ablated part. In response, artificial nerve conduits made of artificial materials have been reported, but the efficacy of the nerve regeneration still needs improvement. The purpose of this study is to investigate the efficacy and mechanism of the Bio three-dimensional (3D) conduit composed of xeno-free human induced pluripotent stem cell–derived mesenchymal stem cells (iMSCs). The 5-mm nerve gap of the sciatic nerve in immunodeficient rats was bridged with the Bio 3D conduit or silicone tube. Functional and histological recovery were assessed at 8 weeks after surgery. The regenerated nerve in the Bio 3D group was significantly superior to that in the silicone group based on morphology, kinematics, electrophysiology, and wet muscle weight. Gene expression analyses demonstrated neurotrophic and angiogenic factors. Macroscopic observation revealed neovascularization both inside and on the surface of the Bio 3D conduit. Upon their subcutaneous implantation, iMSCs could induce angiogenesis. The Bio 3D conduit fabricated from iMSCs are an effective strategy for nerve regeneration in animal model. This technology will be useful in future clinical situations.

Experimental and numerical investigation of a polypropylene orthotic device for assistance in level ground walking

This study investigates the use of an orthotic device for improving pathologic gait lacking a heel-strike and its effect on the joint loads. The orthosis is fabricated from 10-mm thick polypropylene sheets joined together using a bolted joint. The gait trials are recorded using a Qualisys motion capture system and Kistler's force platform. The data recorded in this study comprise five male and five female participants, executing level ground gait under barefoot, shod and orthotic conditions. Computed tomography reconstructed foot bone-tissue model and computer-aided design model of the orthosis are used to predict the mechanical behaviour with and without orthosis under static loading. A one-way analysis of variance is conducted to compare the peak gait parameters in the early and late stance phase between the three walking conditions. The experimental results show that the orthosis reduces the peak joint forces and the rate of change of moment at the hip, knee and ankle joints. The finite element analysis results present a decrease in foot plantar pressure from 0.74 to 0.32 MPa with orthotic usage. The results of this study indicate that the orthosis can eliminate the heel-ground gap while retaining sufficient ankle motion and providing peak joint force reduction.