Photobiomodulation at a wavelength of 633 nm leads to faster functional recovery than 804 nm after facial nerve injury

Photobiomodulation as a Potential Therapy for Erectile Function: A Preclinical Study in a Cavernous Nerve Injury Model

PURPOSE

To identify the optimal photobiomodulation (PBM) parameters using molecular, histological, and erectile function analysis in cavernous nerve injury.

MATERIALS AND METHODS

A cavernous nerve injury was induced in 8-week-old C57BL/6J male mice that were subsequently divided randomly into age-matched control groups. Erectile function tests, penile histology, and Western blotting were performed 2 weeks after surgery and PBM treatment.

RESULTS

The PBM treatment was administered for five consecutive days with a light-emitted diode (LED) device that delivers 660 nm±3% RED light, and near infra-red 830 nm±2% promptly administered following nerve-crushing surgery and achieved a notable restoration of erectile function approximately 90% of the control values. Subsequent in-vitro and ex-vivo analyses revealed the regeneration of neurovascular connections in both the dorsal root ganglion and major pelvic ganglion, characterized by the sprouting of neurites. Furthermore, the expression levels of neurotrophic, survival, and angiogenic factors exhibited a substantial increase across all groups subjected to PBM treatment.

CONCLUSIONS

The utilization of PBM employing LED with 660 nm, 830 nm, and combination of both these wavelengths, exhibited significant efficacy to restore erectile function in a murine model of cavernous nerve injury. Thus, the PBM emerges as a potent therapeutic modality with notable advantages such as efficacy, noninvasiveness, and non-pharmacological interventions for erectile dysfunction caused by nerve injury.

Research advancements on nerve guide conduits for nerve injury repair

Peripheral nerve injury (PNI) is one of the most serious causes of disability and loss of work capacity of younger individuals. Although PNS has a certain degree of regeneration, there are still challenges like disordered growth, neuroma formation, and incomplete regeneration. Regarding the management of PNI, conventional methods such as surgery, pharmacotherapy, and rehabilitative therapy. Treatment strategies vary depending on the severity of the injury. While for the long nerve defect, autologous nerve grafting is commonly recognized as the preferred surgical approach. Nevertheless, due to lack of donor sources, neurological deficits and the low regeneration efficiency of grafted nerves, nerve guide conduits (NGCs) are recognized as a future promising technology in recent years. This review provides a comprehensive overview of current treatments for PNI, and discusses NGCs from different perspectives, such as material, design, fabrication process, and composite function.

The effect of photobiomodulation therapy in common maxillofacial injuries: Current status

The use of photobiomodulation therapy (PBMT) may be used for treating trauma to the maxillofacial region. The effects of PBMT on maxillofacial injuries were discussed in this review article. The electronic databases Pubmed, Scopus, and Web of Science were thoroughly searched. This review included in vitro, in vivo, and clinical studies describing how PBMT can be used in maxillofacial tissue engineering and regenerative medicine. Some studies suggest that PBMT may offer a promising therapy for traumatic maxillofacial injuries because it can stimulate the differentiation and proliferation of various cells, including dental pulp cells and mesenchymal stem cells, enhancing bone regeneration and osseointegration. PBMT reduces pain and swelling after oral surgery and tooth extraction in human and animal models of maxillofacial injuries. Patients with temporomandibular disorders also benefit from PBMT in terms of reduced inflammation and symptoms. PBMT still has some limitations, such as the need for standardizing parameters. PBMT must also be evaluated further in randomized controlled trials in various maxillofacial injuries. As a result, PBMT offers a safe and noninvasive treatment option for patients suffering from traumatic maxillofacial injuries. PBMT still requires further research to establish its efficacy in clinical practice and determine the optimal parameters.

A Nonrandomized Trial of the Effects of Near-Infrared Photobiomodulation Therapy on Bell's Palsy with a Duration of Greater Than 8 Weeks

Objective: To determine whether photobiomodulation therapy (PBMT) by class IV Multiwave Locked System laser treatment as an adjunctive therapy could relieve symptoms in patients with Bell's palsy with a duration of greater than 8 weeks. Materials and methods: This nonrandomized controlled trial was conducted from January 2020 to December 2022. Patients were eligible if they had Bell's palsy with a duration of greater than 8 weeks at the out-patient department of otorhinolaryngology in Beijing Tongren Hospital. The control group consisted of patients recruited between January 1, 2020, and December 31, 2020. The PBMT group consisted of patients recruited between January 1, 2021, and December 31, 2022. In this study, the PBM used has a wavelength of 808 and 905 nm, 1.2 W power (808 nm is 1 W, 905 nm is 200 mW), continuous mode emission (808 nm) and pulsed mode emission (905 nm), 8.35 J/cm2 dosimetry, administered 3 times per week, 72 times of total treatment. The primary outcome measures included the House-Brackmann facial nerve grading system, the Sunnybrook facial grading system, and the Facial Clinimetric Evaluation Scale (FaCE). Secondary outcome measures comprised electroneurography, electromyography, and the blink reflex. Results: A total of 54 participants were included (27 in the control group and 27 in the photobiomodulation group). After 6 months, the House-Brackmann grading system [risk difference, -0.59, confidence interval (95% CI), -0.81 to -0.38, relative risk, 0.27, 95% CI, 0.13-0.56, p < 0.001], Sunnybrook facial grading system (21.14, 95% CI, 11.71-30.58; p < 0.001), and FaCE (-0.20, 95% CI, 0.41-0.02; p = 0.07) had significant difference between the two groups. Latency of ala nasi muscle (10.92, 95% CI, 5.58-16.27; p < 0.001) was not statistically significant after treatment compared with the control group; however, most of the electrophysiological examinations have significant difference between the two groups, respectively. Conclusions: The results of this study suggest that PBMT may relieve symptoms for patients with Bell's palsy with a duration of greater than 8 weeks. Trial Registration: ClinicalTrials.gov Identifier: NCT05585333.

Morphofunctional Improvement of the Facial Nerve and Muscles with Repair Using Heterologous Fibrin Biopolymer and Photobiomodulation

Peripheral nerve injuries impair the patient's functional capacity, including those occurring in the facial nerve, which require effective medical treatment. Thus, we investigated the use of heterologous fibrin biopolymer (HFB) in the repair of the buccal branch of the facial nerve (BBFN) associated with photobiomodulation (PBM), using a low-level laser (LLLT), analyzing the effects on axons, muscles facials, and functional recovery. This experimental study used twenty-one rats randomly divided into three groups of seven animals, using the BBFN bilaterally (the left nerve was used for LLLT): Control group-normal and laser (CGn and CGl); Denervated group-normal and laser (DGn and DGl); Experimental Repair Group-normal and laser (ERGn and ERGl). The photobiomodulation protocol began in the immediate postoperative period and continued for 5 weeks with a weekly application. After 6 weeks of the experiment, the BBFN and the perioral muscles were collected. A significant difference (p < 0.05) was observed in nerve fiber diameter (7.10 ± 0.25 µm and 8.00 ± 0.36 µm, respectively) and axon diameter (3.31 ± 0.19 µm and 4.07 ± 0.27 µm, respectively) between ERGn and ERGl. In the area of muscle fibers, ERGl was similar to GC. In the functional analysis, the ERGn and the ERGI (4.38 ± 0.10) and the ERGI (4.56 ± 0.11) showed parameters of normality. We show that HFB and PBM had positive effects on the morphological and functional stimulation of the buccal branch of the facial nerve, being an alternative and favorable for the regeneration of severe injuries.