Facial Nerve In Rabbits Research Articles

A biodegradable and flexible neural interface for transdermal optoelectronic modulation and regeneration of peripheral nerves

Optoelectronic neural interfaces can leverage the photovoltaic effect to convert light into electrical current, inducing charge redistribution and enabling nerve stimulation. This method offers a non-genetic and remote approach for neuromodulation. Developing biodegradable and efficient optoelectronic neural interfaces is important for achieving transdermal stimulation while minimizing infection risks associated with device retrieval, thereby maximizing therapeutic outcomes. We propose a biodegradable, flexible, and miniaturized silicon-based neural interface capable of transdermal optoelectronic stimulation for neural modulation and nerve regeneration. Enhancing the device interface with thin-film molybdenum significantly improves the efficacy of neural stimulation. Our study demonstrates successful activation of the sciatic nerve in rodents and the facial nerve in rabbits. Moreover, transdermal optoelectronic stimulation accelerates the functional recovery of injured facial nerves.

Correlation of nerve conduction velocity and the number of newly created axons in the regeneration of the facial nerve in rabbits after application of platelet-rich plasma

Introduction/Objective. Quality of life before and after mono- and bimaxillary surgery may vary from patient to patient depending on psychological assessment score. The aim of this study was to compare the quality of life before and six months after orthognathic surgery in correlation with a presurgical psychological assessment of patients with class III skeletal deformity, assuming that patients with low psychological assessment results might have a lower quality of life after surgery despite successful treatment results. Methods. For this prospective study, 30 patients (19 female,11 male) were included. Psychological assessment was obtained before, and quality of life before and after surgery in skeletal deformity class III patients. Statistical analysis was done with a statistical package for social science ? SPSS. Results. The overall quality of life significantly improved in all the patients after surgery. Surgical correction of class III deformities provided a significant improvement independent of the type of surgery and the severity of the deformity, as well as gender and age. There were significant differences in post-surgical quality of life scores between patients with good and poor psychological assessment scores, related to social disability (p < 0.05). Conclusion. Patients with lower preoperative psychological scores experienced a lesser improvement in quality of life, particularly in the domain of social disability. This suggests that additional psychological treatment of these patients could further improve the beneficial effects of orthognathic surgery on postoperative quality of life.

Assessment of efficacy of platelet-rich plasma application in regeneration of the facial nerve in rabbits

Background/Aim. The injuries of the facial nerve lead to paralysis of the mimic musculature, which is conditioned by functional disorders accompanied by deformity of varying degrees depending on the intensity and location of the injury. Surgical treatment is a method of choice to treat an injured nerve. Injuries in the parotid lodge area are repaired by direct neurosuture in combination with platelet-rich plasma (PRP). Methods. The experimental study was carried out on 48 chinchilla male rabbits (Oryctolagus cuniculus), of about the same weight (2,500?3,000 gr), aged between 3 and 4 months in two surgical stages, in two different periods ? six and ten weeks after the first surgical procedure. The animals were divided into four groups: Group I (suture); Group II [suture and fibrin glue (FG)]; Group III (suture and PRP); Group IV (sutures, FG, and PRP). Each group had two subgroups based on the duration of the experiment (six and ten weeks). A part of the dissected nerve in the length of 5 mm was subjected to histologic verification, where the number of axons and Schwann cells was determined and expressed numerically based on the histological sample of the tissue of the observed nerve. The extent of the presence of connective tissue and the degree of neo-vascularisation is shown by the description of histological samples by grades (connective tissue 1-4, neovascularisation 1-3). Results. Our results showed that all parameters of re-generation of damaged nerve showed a significantly higher regeneration efficiency after six and ten weeks of intervention in groups treated with PRP therapy with or without using FG. Conclusion. The use of PRP and the stimulating effect of activated growth factors results in the regeneration of the facial nerve in the sense of replication of the Schwann cells and the number of axons, with a high degree of neovascularization and minimal proliferation of connective tissue, which histologically corresponds to a healthy nerve.

Effects of Postoperative Radiotherapy on Vascularized Nerve Graft for Facial Nerve Repair in a Rabbit Model

High fractional dose radiotherapy (RT) produces better radiobiological results. However, a concern always exists regarding radiation-induced damage to normal tissues, in particular, the peripheral nerves. In the present study, we assessed the effects of postoperative RT on vascularized facial nerve grafts in a rabbit model. Surgical defects were created bilaterally on the upper buccal branches of the facial nerve in rabbits. One side received a vascularized nerve graft (VNG), and the other side received a free nerve graft (FNG). RT was planned in 1 group at 1month postoperatively. The dose was equivalent to 60Gy for each side. Evaluation of the facial performance, electrophysiologic monitoring, histologic studies, toluidine blue staining, and scanning electron microcopy were performed at 3months after RT. In the RT group, the pathological changes included surrounding tissue fibrosis, nerve cell shrinkage, Schwann cell injury, and demyelination. Compared with the control group, postoperative RT had no obvious effect on the regeneration and functional recovery of the facial nerves. The functional recovery rate of the VNG was faster than that of the FNG in the RT group. In addition, the difference in the nerve conduction velocity and amplitude was statistically significant between the 2 groups. Postoperative RT influenced the functional recovery of facial nerves to a certain degree. The use of VNGs could alleviate the adverse effects of RT on facial nerve regeneration.

Chitosan conduits combined with nerve growth factor microspheres repair facial nerve defects.

Microspheres containing nerve growth factor for sustained release were prepared by a compound method, and implanted into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. In addition, chitosan conduits combined with nerve growth factor or normal saline, as well as autologous nerve, were used as controls. At 90 days post-surgery, the muscular atrophy on the right upper lip was more evident in the nerve growth factor and normal sa-line groups than in the nerve growth factor-microspheres and autologous nerve groups. physiological analysis revealed that the nerve conduction velocity and amplitude were significantly higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. Moreover, histological observation illustrated that the di-ameter, number, alignment and myelin sheath thickness of myelinated nerves derived from rabbits were higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. These findings indicate that chitosan nerve conduits bined with microspheres for sustained release of nerve growth factor can significantly improve facial nerve defect repair in rabbits.

Repair of Rabbit Facial Nerve with Amniotic Extracellular Matrix Based on Biological Material

Objective: To evaluate the effects of amniotic extracellular matrix (AECM) on the repairation of facial nerve in rabbits. Methods: The transected nerve ends of the facial nerves of rabbits were then repaired with the AECM nerve conduit or an autologous nerve graft. After 3 months, the animals’ neural conductive velocity were determined. The myelinated fibers across the specimen were counted with histological examination. Results: The total count of medullated nerve fibers varied significantly, but the nerve conduction velocity had no significance between the AECM grafts and the autologous nerve grafts. Conclusion: AECM could become the biocompatible material for repairing the peripheral nerves.

Autogenous standard versus inside-out vein graft to repair facial nerve in rabbits

To evaluate autogenous vein grafts and inside-out vein grafts as conduits for the defects repair in the rabbit facial nerves. The 10 mm segments of buccal division of facial nerve were transected for 48 rabbits in this study. Then the gaps were immediately repaired by autogenous vein grafts or inside-out vein grafts in different groups. All the animals underwent the whisker movement test and electrophysiologic test during the following 16 weeks at different time points postoperatively. Subsequently, the histological examination was performed to observe the facial nerve regeneration morphologically. At 8 weeks after operation, the facial nerve regeneration has significant difference between the experimental group and the control group in electrophysiologic test and histological observation. However, at the end of this study, 16 weeks after operation, there was no significant difference between inside-out vein grafts and standard vein grafts in enhancing peripheral nerve regeneration. This study suggest that both kinds of vein grafts play positive roles in facial nerve regeneration after being repaired immediately, but the autogenous inside-out vein grafts might accelerate and facilitate axonal regeneration as compared with control.

Effects of hyperbaric oxygen therapy on facial nerve regeneration

Conclusion. Hyperbaric oxygen treatment (HBOT) promoted an increase of the mean axonal diameter in the group evaluated 2 weeks after lesion induction, which suggests a more advanced regeneration process. However, the number of myelin nerve fibers of the facial nerve of the rabbits was similar when compared to the control and treatment groups, in both evaluation periods. Objective. To evaluate the effect of HBOT on the histological pattern of the facial nerve in rabbits exposed to a nerve crush injury. Materials and methods. Twenty rabbits were exposed to facial nerve crush injury. Ten rabbits received HBOT, 10 rabbits comprised the control group. The rabbits were sacrificed 2 and 4 weeks after the trauma. Qualitative morphological analysis, measurement of the external axonal diameters and myelin fiber count were carried out in an area of 185 000 µm2. Results. There was an increase in the area of the axons and thicker myelin in the 2 weeks treatment group in comparison with the control group. The mean diameter of the axons was of 2.34 µm in the control group and of 2.81 µm in the HBOT group, with statistically significant differences. The 2 week control group had a mean number of myelin fibers of 1865.2±664, and the HBOT group had a mean number of 2026.3±302; this was not statistically significant. The 4 week control group presented a mean of 2495.1±479 fibers and the HBOT group presented a mean of 2359.9±473; this was not statistically significant.

Regeneração pós-traumática do nervo facial em coelhos

A paralisia facial periférica traumática constitui-se em afecção freqüente. OBJETIVO: estudo da regeneração pós-traumática do nervo facial em coelhos, por avaliação funcional histológica dos nervos traumatizados comparados aos normais contralaterais. METODOLOGIA: Vinte coelhos foram submetidos à compressão do tronco do nervo facial esquerdo e sacrificados após duas (grupo AL), quatro (BL) e seis (CL) semanas da lesão. A comparação entre os grupos foi feita pelas densidades total e parcial de axônios mielinizados. ESTUDO ESTATÍSTICO: método de Tukey (p < 0,05). RESULTADOS: Houve recuperação funcional parcial após duas, e completa após cinco semanas. Na análise qualitativa, verificou-se em AL um padrão degenerativo, com maior processo inflamatório tecidual. Em BL, sinais de regeneração neural, praticamente completa em CL. Os nervos normais (N) apresentaram DT média de 15705,59 e DP média de 21800,75. O grupo BL revelou DT média de 10818,55 e DP média de 15340,56 e o CL, DT média de 13920,36 e DP média de 16589,15. BL obteve 68,88%, e o grupo CL, 88,63% da DT de N. N mostrou DP maior que os lesados; porém, esta não evidenciou diferença estatística entre BL e CL. A DT dos nervos revelou-se um método analítico mais fidedigno do que a DP estudada.

Posttraumatic facial nerve regeneration in rabbits.

Posttraumatic facial paralysis is a frequent disease. This work studies posttraumatic regeneration of the facial nerve in rabbits. Functional and histological analysis compared injured and normal nerves on opposite sides. The left facial nerve trunk of twenty rabbits were subjected to compression lesion, and sacrificed after two (subgroup AL), four (BL) and six (CL) weeks. Comparison between groups was made by analysing total and partial densities of myelinated axons. Tukey Method (p<0.05). There was partial functional recovery after two weeks, and complete recovery after five weeks. Qualitative analysis demonstrated a degenerative pattern in the AL group, with an increased tissue inflammatory process. Evident regeneration signs were observed in the BL group, and almost complete regeneration was seen in the CL group. Normal nerves (N) had an average TD of 15705.59 and average PD of 21800.75. The BL group had an average TD of 10818.55 and an average PD of 15340.56. The CL group had an average TD of 13920.36 and an average PD of 16589.15. The BL group had an average TD of N equal to 68.88%, and the CL group had an average TD of N equal to 88,63% (statistically significant). N showed a significant higher PD than injured nerves. However, this was not statistically different between BL and CL subgroups. Nerve DT was a more reliable method than PD in this study.

Facial nerve repair with expanded polytetrafluoroethylene and collagen conduits: An experimental study in the rabbit

Purpose: This study evaluated autogenous nerve grafts and expanded polytetrafluoroethylene (e-PTFE) and collagen tubes as conduits for the repair of continuity defects in the facial nerve of rabbits. Materials and Methods: The buccal division of 24 facial nerves was isolated, transected, and separated 10 mm. The gap between the 2 nerve ends was then repaired with an autologous nerve graft or an e-PTFE or collagen conduit. Fifteen days and 1, 2, and 4 months after the procedure, the animals were subjected to electrophysiologic tests, killed, and the nerves were removed for histologic examination. Results: At 15 days postsurgery, no regeneration was observed through the e-PTFE and collagen tubes or accross the autologous nerve grafts at the midpoint of the specimens. However, regeneration across the chambers and autologous nerve grafts was seen in the following 4 months, although the number of axons regenerated was small. Conclusions: The results of the study indicate that e-PTFE and collagen tubing may be effective in the repair of continuity defects in peripheral nerves. However, further research will be necessary for generalization of this procedure. © 2000 American Association of Oral and Maxillofacial Surgeons

Facial nerve regeneration through autologous nerve grafts: A clinical and experimental study

Human facial nerve regeneration was compared in two systems: autologous neural cable grafts (N = 56) and direct end-to-end anastomosis (N = 34). The data were analyzed based on the following criteria: facial symmetry and muscle tone at rest, degree of total facial reinnervation, voluntary motion, synkinesis, and electrophysiologic testing. Facial tone and symmetry at rest, and electrophysiologic tests were similar, while voluntary motion and facial reinnervation were decreased and synkinesis increased in the autologous cable graft repairs. Electrophysiologic tests failed to distinguish between the two repair methods in successful regenerates. Neural cable grafts were associated with more mass movement and less fine precise emotive facial movement. Excellent cable graft repair results diminish with time because of continual progressive synkinesis, which may take up to 4 years to develop. Eight-millimeter neural cable graft repairs of the buccal division of the facial nerve in rabbits (N = 8) demonstrate, at 5 weeks, equal myelinated and more unmyelinated axons than in the normal nerve controls. Neural cable graft repairs demonstrate two features not found in the normal nerve: 1. myelin debris and 2. two subpopulations of axons--extrafascicular and intrafascicular. Myelin debris predisposes towards extrafascicular axon regeneration. Extrafascicular axons are the major neurite regenerates (63%). Intrafascicular axons are the major reinnervators of the distal transected nerve stump. Electrophysiologic studies demonstrate decreased conduction velocities which are related to the number and size of myelinated axonal regenerates. The implications for neurite reinnervation of the autologous cable graft and their role in synkinesis are discussed.

Conditions of clinical recovery from partial facial palsy caused by injury to a branch of the facial nerve.

This study was conducted to elucidate the pattern of clinical recovery from partial facial palsy caused by injury to a branch of the facial nerve in rabbits. In the experiment, the state of recovery from palsy was investigated by observing the movement of the m. orbicularis oris of the rabbit at the time of food intake, as well as by observing the evoked wave and muscle contraction caused by nerve stimulation, and the muscle contraction caused by muscle stimulation. Recovery from peripheral facial nerve palsy is complete within 1 month after nerve impairment if over half of the nerve fibers of the impaired nerve are maintained intact without degeneration.