Neuropeptide expression and morphometric differences in crushed alveolar inferior nerve of rats: Effects of photobiomodulation

Abstract

Inferior alveolar nerve (IAN) injuries may occur during various dental routine procedures, especially in the removal of impacted lower third molars, and nerve recovery in these cases is a great challenge in dentistry. Here, the IAN crush injury model was used to assess the efficacy of photobiomodulation (PBM) in the recovery of the IAN in rats following crushing injury (a partial lesion). Rats were divided into four experimental groups: without any procedure, IAN crush injury, and IAN crush injury with PBM and sham group with PBM. Treatment was started 2 days after surgery, above the site of injury, and was performed every other day, totaling 10 sessions. Rats were irradiated with GaAs Laser (Gallium Arsenide, Laserpulse, Ibramed Brazil) emitting a wavelength of 904 nm, an output power of 70 mWpk, beam spot size at target ∼0.1 cm, a frequency of 9500 Hz, a pulse time 60 ns, and an energy density of 6 J/cm. Nerve recovery was investigated by measuring the morphometric data of the IAN using TEM and by the expression of laminin, neurofilaments (NFs), and myelin protein zero (MPZ) using Western blot analysis. We found that IAN-injured rats which received PBM had a significant improvement of IAN morphometry when compared to IAN-injured rats without PBM. In parallel, all MPZ, laminin, and NFs exhibited a decrease after PBM. The results of this study indicate that the correlation between the peripheral nerve ultrastructure and the associated protein expression shows the beneficial effects of PBM.

Anti-cancer effect of dung beetle glycosaminoglycans on melanoma

“…Compared to CON group, CaG5 treated mice group showed upregulation of 192 genes, including Col12a1 involved in cytoskeletal reorganization [20, 21] and Hbb-bt, amino levulinic acid synthase2, erythroid (Alas2) [22, 23], and heparanase (Hpse) [24]. It also showed downregulation of 152 genes, including nuclear RNA export factor (Nxf3) [25], hyaluronan and proteoglycan link protein1 (Hapln1) [26], G protein-coupled receptor17 (Gpr17) [27, 28], and myelin protein zero (Mpz) [29–31]. These data suggest that collagen type XII alpha1 was up-regulated while nuclear RNA export factor (Nxf3) was down-regulated by CaG5 treatment, indicating their potential as therapeutic markers for anti-cancer agents.…”

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

“…These studies fail in the accurate inclusion and exclusion criteria. Additionally, only two works [ 34 , 36 ] described a clear sample size calculation, while in the other articles [ 35 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ], the authors only stated that “efforts were made to minimise the number of animals used and their suffering in accordance with ethical guidelines for investigations of experimental pain in conscious animals”. All of the experimental setups were approved by the relevant Regional Ethics Committee.…”

“…Unfortunately, many articles [ 34 , 35 , 38 , 40 , 42 , 43 , 44 , 45 , 46 ] showed a high risk of bias due to a lack of randomisation and/or blinding of the procedure and were excluded ( Supplementary Tables S1 and S2 ). Therefore, four articles [ 36 , 37 , 39 , 41 ] ( Table 1 ) were selected, and the work of Diker et al [ 36 ] was given a higher score using the ARRIVE guidelines ( Supplementary Table S1 ).…”

“…Regarding nerve regeneration, as suggested by Diker et al [ 36 ], most of the original studies involve animal sciatic nerves, and only a small number investigated the effects of PBM following the injury of the trigeminal nerve branches. Despite not being included in the review process due to nonadherence to many points of the ARRIVE guidelines, nine comparative research articles [ 34 , 35 , 38 , 40 , 42 , 43 , 44 , 45 , 46 ] using a total of 273 rats showed the effects of PBM at different wavelengths and phototherapy parameters on the regeneration of trigeminal nerve branches, neurosensory recovery and pain. These effects are most likely the consequence of cell physiology modulation, resulting in a decrease in substance P (SP), vanilloid transient potential receptor of subtype-1 (TRPV1), peptide related to the calcitonin gene [ 34 ], matrix metalloproteinases [ 35 ], laminin, myelin protein zero, neurofilaments [ 38 ] and brain-derived neurotrophic factor [ 45 ], and an increase in the nerve growth factor level [ 45 ].…”

“…Additionally, consistent results showed that persistent pain states are mediated by cooperative actions of TRPV1, glutamate, SP and calcitonin gene-related peptide (CGRP). However, Martins et al [ 38 ] observed that a decrease in TRPV1 and an increase in glutamatergic transmission induced by PBM with 904-nm light is an accredited way to explain the reduction of neuropathic pain related to the trigeminal nerve. Calcium may have also a role in this issue.…”