Mitochondrial Bioenergetic, Photobiomodulation and Trigeminal Branches Nerve Damage, What’s the Connection? A Review

Abstract

Background: Injury of the trigeminal nerve in oral and maxillofacial surgery can occur. Schwann cell mitochondria are regulators in the development, maintenance and regeneration of peripheral nerve axons. Evidence shows that after the nerve injury, mitochondrial bioenergetic dysfunction occurs and is associated with pain, neuropathy and nerve regeneration deficit. A challenge for research is to individuate new therapies able to normalise mitochondrial and energetic metabolism to aid nerve recovery after damage. Photobiomodulation therapy can be an interesting candidate, because it is a technique involving cell manipulation through the photonic energy of a non-ionising light source (visible and NIR light), which produces a nonthermal therapeutic effect on the stressed tissue. Methods: The review was based on the following questions: (1) Can photo-biomodulation by red and NIR light affect mitochondrial bioenergetics? (2) Can photobiomodulation support damage to the trigeminal nerve branches? (preclinical and clinical studies), and, if yes, (3) What is the best photobiomodulatory therapy for the recovery of the trigeminal nerve branches? The papers were searched using the PubMed, Scopus and Cochrane databases. This review followed the ARRIVE-2.0, PRISMA and Cochrane RoB-2 guidelines. Results and conclusions: The reliability of photobiomodulatory event strongly bases on biological and physical-chemical evidence. Its principal player is the mitochondrion, whether its cytochromes are directly involved as a photoacceptor or indirectly through a vibrational and energetic variation of bound water: water as the photoacceptor. The 808-nm and 100 J/cm2 (0.07 W; 2.5 W/cm2; pulsed 50 Hz; 27 J per point; 80 s) on rats and 800-nm and 0.2 W/cm2 (0.2 W; 12 J/cm2; 12 J per point; 60 s, CW) on humans resulted as trustworthy therapies, which could be supported by extensive studies.

Photobiomodulation by Near-Infrared 980-nm Wavelengths Regulates Pre-Osteoblast Proliferation and Viability through the PI3K/Akt/Bcl-2 Pathway

“…Photobiomodulation events are the result of intramural cell signalling cascades, with the start point represented by the photoacceptor, which activates second messengers and culminates with the modulation of tissue homeostasis. As previously discussed [ 3 , 13 , 41 , 54 ] and also displayed in Figure S2 , the primary target can be identified in the cytochromes of the mitochondrial respiratory chain, nitrosothiol compounds, bound water, and lipids. After the interaction with red and particularly infrared light, targets modify their energetic and vibrational state, supporting the release of ATP, ROS, nitric oxide, and calcium through the opening of voltage-dependent receptors and release from intra-organellar-sequestered reserves.…”

“…Following our previous reviews on PBM [ 3 , 13 , 41 ], the second most frequent reason for exclusion was the unsuitability of the parameters’ reproducibility, as described by Tunér and Jenkins [ 42 ]. The 12 selected papers employed the following wavelengths: one article used 905 nm [ 43 ], two used 910 nm [ 44 , 45 ] and 980 nm [ 40 , 46 ], three used 915 nm [ 47 , 48 , 49 ], and four used 940 nm [ 50 , 51 , 52 , 53 ].…”

“…It has been clarified that different wavelengths interact with photoacceptors differently, according to their coefficient of absorption. From 450 nm to >900 nm, the affinity of the cytochrome-c oxidase decreases, whereas the affinity of water and lipids increases [ 13 , 54 ]. Therefore, different wavelengths can act through different cellular pathways based on their spectrum.…”

“…The resulting medical topic is commonly known as low-level laser/light therapy (LLLT), but the more appropriate term photobiomodulation (PBM) therapy was recently affirmed. The reliability of the photobiomodulatory event is strongly based on biological and physical-chemical evidence [ 13 , 14 ].…”

“…It should, however, be emphasised that the term PBM describes the event of light interaction modulating cellular metabolism, but the players involved may change as the wavelength moves from visible light, through NIR (780–890 nm), up to the 905–1064 nm range, as we recently discussed [ 13 , 14 ]. Cytochromes, bound-water, voltage-dependent receptors, lipids, and nitrosothiol (thionitrite) compounds are able to function as photoacceptors, but do so in selective modalities with respect to the wavelengths involved [ 13 ].…”