The Action of Topical Basic Fibroblast Growth Factor in Facial Nerve Regeneration

The effectiveness of concentrated growth factor in facial nerve crush injury

AIM

To evaluate the effect of concentrated growth factor (CGF) on regeneration of facial nerve after crush injury.

MATERIALS AND METHODS

Fourteen rats were randomized into two groups. The control group (CG) (n = 7) received a crush injury to the right facial nerve. The CGF group (CGFG) (n = 7) received a crush injury to the right facial nerve and concentrated growth factor prepared from their own blood thereafter. Left facial nerves were used for functional comparison. Nerve function was evaluated using whisker movements and electromyography. Histologic properties were evaluated using hematoxylin and eosin and Masson-trichrome staining, and immunohistochemical properties were evaluated using Neurofilament-H and Anti-Tau degeneration markers.

RESULTS

In the CGFG, whisker functions began to recover earlier and recovered more quickly compared with the CG. The CG showed significantly prolonged latency and reduced amplitudes in the first week compared with the CGFG (p < 0.05). Recordings of 4th-week latency and amplitudes were similar to the preoperative period in the CGFG (p > 0.05), whereas recordings of the same week were significantly worse in the CG (p < 0.05). Edema and fibrosis were also more pronounced in the CG compared with the CGFG. Neurofilament-H and Anti-Tau were at significantly high levels in the CG (p < 0.05).

CONCLUSION

Concentrated growth factor promotes recovery in facial crush injury and may prove a cost-effective, practical, and effective treatment choice in peripheral nerve injury.

Biomaterial-Based bFGF Delivery for Nerve Repair

Diseases in the nervous system are common in the human body. People have to suffer a great burden due to huge economic costs and poor prognosis of the diseases. Many treatment modalities are now available that can make recovery better. Managing nutritional factors is also helpful for such diseases. The basic fibroblast growth factor (bFGF) is one of the major nutritional factors, which plays a crucial role in organogenesis and tissue homeostasis. It plays a role in cell proliferation, migration, and differentiation, thereby regulating angiogenesis and wound healing and repair of the muscle, bone, and nerve. The study on how to improve the stability of bFGF to increase the treatment effect for different diseases has garnered tremendous attention. Biomaterials are the popular methods to improve the stability of bFGF because they are safe for the living body as they are biocompatible. Biomaterials can be loaded with bFGF and delivered locally to achieve the goal of sustained bFGF release. In the present review, we report different types of biomaterials that are used for bFGF delivery for nerve repair and briefly report how the introduced bFGF can function in the nervous system. We aim to provide summative guidance for future studies about nerve injury using bFGF.

Sustained Release In Situ Thermogelling Hydrogel of Cerebrolysin for Treatment of Facial Nerve Axotomy in Rats

PURPOSE

The most essential principle in managing facial nerve (FN) injury is proper diagnosis and early treatment. This study evaluated local application of different concentrations and injection intervals of Cerebrolysin hydrogel (CBLH) for facial nerve axotomy (FNA) treatment. We hypothesized that local application of CBLH may provide a sustained release of Cerebrolysin and enhance neural regeneration.

METHODS

The authors implemented a randomized, controlled, blinded animal study. The sample was composed of the right FN. Functionally, eye-blink reflex was evaluated 2 and 4 weeks postoperatively. All rats were euthanized after 4 weeks, and nerve regeneration was evaluated histopathologically and immunohistochemically (IHC) with antibody against neurofilament (anti-NF) and S100 proteins. Descriptive and correlation statistics were computed, and the P value was set at .05.

RESULTS

The sample was composed of 72 adult male rats equally allocated into 8 groups. Groups I and V served as control groups and were injected with phosphate buffered saline once and four times, respectively. Rest of the groups were injected with 5%, 10%, and 15% CBLH once in groups II, III, IV and weekly in groups VI, VII, and VIII. CBLH showed statistically significant FN regeneration by enhancing Schwann and axonal growth compared to control group especially with single injection of 10%, 15%, and 5% 4-time injections, where the P value was less than .001. Significant improvement of eye-blink reflex was correlated with structural improvement associated with CBLH.

CONCLUSION

Finally, CBLH enhanced nerve regeneration and rehabilitation after FNA in rats. Therefore, it could be considered as an alternative treatment of FNA. More experimental and clinical trials should be considered to detect the effectiveness of CBLH in neural regeneration.

Efficacy of platelet-rich fibrin and tacrolimus on facial nerve regeneration: an animal study

This study was performed to investigate the effect of platelet-rich fibrin membrane (PRFM), alone and with topical tacrolimus application, on regeneration of the crushed facial nerve (FN). Thirty healthy 7-week-old albino rats were used. The left FN was damaged by crushing in all rats. Three random groups of rats were formed: group 1, untreated; group 2, treated with PRFM; group 3, treated with PRFM plus topical tacrolimus. Functional recovery and histological and immunohistochemical evaluations were performed 4 and 8 weeks later. Anti-S100 was used to detect myelin sheath. At 4 weeks, blinking reflex recovery was more rapid in group 3 than in groups 2 and 1 (4.30 ± 0.48, 3.40 ± 0.52, and 2.20 ± 0.42, respectively); the difference was statistically significant (P = 0.001). Histologically, group 3 showed more apparent normal FN structures than the other groups. Immunohistochemical caspase-3 evaluation of the axon area revealed a significant difference between group 2 (PRFM alone; 8.67 ± 0.029) and group 3 (PRFM plus topical tacrolimus; 4.42 ± 0.028) (P = 0.001). Group 3 showed the greatest positive staining in the myelin sheath. Based on the results of this animal study, clinical studies should be performed to determine whether the combination of PRF and tacrolimus also improves the outcome of nerve regeneration in humans.

Hypoglossal-facial nerve reconstruction using a Y-tube-conduit reduces aberrant synkinetic movements of the orbicularis oculi and vibrissal muscles in rats

The facial nerve is the most frequently damaged nerve in head and neck trauma. Patients undergoing facial nerve reconstruction often complain about disturbing abnormal synkinetic movements of the facial muscles (mass movements, synkinesis) which are thought to result from misguided collateral branching of regenerating motor axons and reinnervation of inappropriate muscles. Here, we examined whether use of an aorta Y-tube conduit during reconstructive surgery after facial nerve injury reduces synkinesis of orbicularis oris (blink reflex) and vibrissal (whisking) musculature. The abdominal aorta plus its bifurcation was harvested (N = 12) for Y-tube conduits. Animal groups comprised intact animals (Group 1), those receiving hypoglossal-facial nerve end-to-end coaptation alone (HFA; Group 2), and those receiving hypoglossal-facial nerve reconstruction using a Y-tube (HFA-Y-tube, Group 3). Videotape motion analysis at 4 months showed that HFA-Y-tube group showed a reduced synkinesis of eyelid and whisker movements compared to HFA alone.

Hepatocyte growth factor and basic fibroblast growth factor regulate atrial fibrosis in patients with atrial fibrillation and rheumatic heart disease via the mitogen-activated protein kinase signaling pathway

The aim of this study was to investigate the interrelation between basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF) and atrial fibrosis in patients with atrial fibrillation (AF) and rheumatic heart disease (RHD), and to explore the possible molecular mechanisms underlying this interrelation. Twenty patients with RHD who were scheduled for valve replacement were divided into two groups, comprising 10 cases with AF and 10 cases with sinus rhythm (SR). Clinical data were collected and a small sample of aseptic left atrial appendage was collected by the surgeon. Hematoxylin and eosin (H&E) and Masson's trichrome-stained sections were used to evaluate the cross-sectional area and level of fibrosis, respectively. The expression levels of bFGF and HGF were assessed using immunohistochemistry. The phosphorylation levels of mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (MEK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 in atrial tissue were measured using western blotting. Compared with the SR group, myocardial cell diameter was significantly expanded and there was increased collagen deposition in the AF group (P<0.05). The distribution of bFGF in the AF group was significantly higher than that in the SR group (P<0.05); however, HGF levels were significantly lower in the AF group (P<0.05). The phosphorylation levels of MEK1/2, ERK1/2, JNK1/2 and p38 in the AF group were significantly higher than those in the SR group (P<0.05). The results indicated that bFGF may promote the development of atrial fibrosis, while HGF may function in an opposite manner in patients with AF and RHD. The mitogen-activated protein kinase (MAPK) signaling pathway may be the molecular basis for these roles in atrial fibrosis.

Experimental video analysis of eye blink reflex in a primate model

BACKGROUND

The establishment of reliable methods for functional assessment in experimental models of peripheral nerve regeneration is crucial.

METHODS

We present a straightforward method for video analysis of the eye blink reflex in a model of facial nerve damage in a nonhuman primate (Callithrix sp.).

RESULTS

Our 6-level dynamic analysis demonstrated good reproducibility between independent observers, as measured by Cohen's kappa index. Our static analysis, which was based on 4 semiautomated metric parameters, showed low correlation during the early stage of facial movement recovery (the first and second weeks), but the correlation was excellent during the later stage of recovery (the third and fourth weeks).

CONCLUSION

Altogether, our results establish a viable and readily accessible method with good reproducibility and correlation for the analysis of functional facial nerve recovery in an experimental model and based on video images of the eye blink reflex.

Experimental model of facial paralysis by nerve compression in primates (Callithrix sp.): a new model of facial paralysis in small nonhuman primates

CONCLUSION

We conclude that facial nerve injury induced by compression is associated with a reasonable time window (4 weeks) that allows possible neurotrophic effects to be analyzed. Additionally, there are no hints of cross-innervation by the contralateral facial nerve or parallel innervation by other nerves in the hemiface ipsilateral to the injured nerve.

OBJECTIVE

The aim of this work was to develop an experimental model of facial nerve injury in nonhuman primates (Callithrix sp.).

METHODS

In this study, individuals of the non-human primate species Callithrix sp. were subjected to three different types of facial nerve injury, and they were observed for 27 days after surgery by video to record their facial movements.

RESULTS

Two types of nerve compression caused severe initial facial paralysis followed by gradual recovery until normal levels were reached at the end of the evaluation period. Injury induced by nerve resection was followed by a complete lack of facial movement recovery.

Platelet-rich plasma: a promising product for treatment of peripheral nerve regeneration after nerve injury

Nerve regeneration includes regrowth of injured axons as well as myelination, restoration of synaptic connections and recovery of physiological functions. Platelet-rich plasma (PRP) is prepared from the patient's own blood and contains growth factors that influence wound healing and used in various surgical fields including oral and maxillofacial surgery. When platelets are activated either ex vivo or in vivo, growth factors and proteins were released from platelets' alpha granules. Recent studies proved that PRP could promote regeneration of injured peripheral nerve. This review focuses on current trials using PRP to promote nerve regeneration and repairment, and proposes potential clinical application of PRP for nerve injury in the future.