Photobiomodulation therapy reduces apoptotic factors and increases glutathione levels in a neuropathic pain model

Abstract

Neuropathic pain (NP) is caused by damage to the nervous system due to reactive oxygen spices (ROS) increase, antioxidants reduction, ATP production imbalance, and induction of apoptosis. In this investigation, we applied low-level laser 660 nm (photobiomodulation therapy) as a new strategy to modulate pain. In order to study the effects of photobiomodulation therapy (660 nm) on NP, chronic constriction injury (CCI) model was selected. Low-level laser of 660 nm was used for 2 weeks. Thermal and mechanical hyperalgesia were measured before and after surgery on days 7 and 14, respectively. Paw withdrawal thresholds were also evaluated. Expression of p2x3, Bax, and bcl2 protein was measured by western blotting. The amount of glutathione (GSH) was measured in the spinal cord by continuous spectrophotometric rate determination method. The results are presented as mean ± SD. Statistical analysis of data was carried out using SPSS 21. CCI decreased the pain threshold, 2-week photobiomodulation therapy significantly increased mechanical and thermal threshold, decreased P2X3 expression (p < 0.001), and increased bcl2 expression (p < 0.01), but it was not effective on the Bax expression. We speculated that although photobiomodulation therapy increased ROS generation, it increased antioxidants such as GSH. Increase in bcl2 is another mitochondrial protection mechanism for cell survival and that pain relief and decrease in P2X3 expression confirm it.

Photobiomodulation induces antinociception, recovers structural aspects and regulates mitochondrial homeostasis in peripheral nerve of diabetic mice

“…On the other hand, daily applications of PBM maintained the observed antinociception for all evaluated period thus suggesting that continuous applications of PMB are needed to achieve a better level of antinociceptive effect. These data corroborate with data from the literature demonstrating that 660 nm wavelength is able of stimulating wound healing in diabetic mice and induces antinociception in rodents submitted to experimental models of neuropathic pain . Also, although PBM treatment was effective in reversing nociception, no changes were observed regarding the blood glucose levels or body weight of animals, which continued to progress with the development of diabetes.…”

Intraspinal Injection of Platelet-Rich Plasma Promotes Regeneration of the Spinal Cord and Improves Locomotor Function by Modulating the Apoptosis and the Wnt Signaling Pathways

“…Since caspase3 production, is the starting point of the executive phase of apoptosis, it is considered the principal indicator of apoptosis (47). It is believed that apoptosis is the main factor in the loss of motor neuron functions after injury (3)(4)(5)48). In our experiment the existence of big cavity size in the SCI and vehicle groups con rm degeneration in the site of injury (Fig.…”

Estudo dos mecanismos moleculares envolvidos na analgesia induzida por tratamento com laser de baixa intensidade na neuropatia periférica diabética experimental

“…On the other hand, daily applications of PBM maintained the observed antinociception for all evaluated period thus suggesting that continuous applications of PMB are needed to achieve a better level of antinociceptive effect. These data corroborate with data from the literature demonstrating that 660 nm wavelength is able of stimulating wound healing in diabetic mice [28] and induces antinociception in rodents submitted to experimental models of neuropathic pain [29][30][31]. Also, although PBM treatment was effective in reversing nociception, no changes were observed regarding the blood glucose levels or body weight of animals, which continued to progress with the development of diabetes.…”