Effects on pain
Tavola n.4
The "gate control theory" hypothesizes the mechanism of action through which the stimulation of the wide-caliber A fibers, inhibits the activity of the nociceptive C fibers, stimulating the SG neuron which closes the painful impulses that reach the transmission cells. T (found in the second and fifth layers of Rexed), from which the spinal-thalamo-cortical route starts. This transmits the painful sensitivity through the reticular mesencephalic substance, through descending neuronal circuits both of excitatory and inhibitory type. The analgesic action of the Laser is linked to the reestablishment of the balance of the "gate control system" through the release of endorphins.
Tavola n.5
During an inflammatory process, neutrophils are the first cells to arrive at the scene of an infection and contribute significantly to the inflammatory response. As neutrophils rotate along the walls of blood vessels, L-Selectin, adhering to their wall, binds to the structure of carbohydrates such as Sialin-L which adheres to the endothelium of the vessel surface. When the neutrophil starts to activate, it replaces the L-selectin with molecular adhesion cells such as the integrins. The latter envelop E-Selectin which appears on the vessel wall under the influence of chemical mediators of inflammation (polysaccharides, cytokine interleukins 1-6-10, Interferon gamma, TNF- αe secreted by CD4-T cells ). Activated neutrophil, then it enters the tissues, where it is attracted by the site of inflammation through chemical mediators such as C3a C5a, chemokines, histamine, prostaglandins (PGE2) and leukotrienes. Neutrophil activation passes through the vessel wall inducing the chemotaxic gradient to focus on the site of infection to engulf and destroy the C3b bacterial coating or tissue damage. In vitro and in vivo studies have shown that the photodynamic action of the Laser facilitates this reparative process.
Tavola n.6
Pain caused by chronic musculoskeletal trauma activates feed-back mechanisms that affect the quality of a person's life. On the one hand, nociceptive fibers stimulate the cells of the posterior horns of the spinal cord and, through the spino-thalamus-cortical route, determine the state of pain sensitivity and the awareness of one's own damage and discomfort. The same trauma, furthermore, through the cytokines, stimulates the hypothalamic-pituitary-adrenal axis, mediating to the reaction of pain stress with release of cortisol, vasopressin. The consequence of this action causes a series of various psycho-somatic disorders that added to those described above, contribute to increase the perception of one's own damage and pain. The low energy density laser interrupts the vicious circle determined by the trauma, reducing both the production of the chemical mediators of inflammation, and at the same time rebalancing the afference of C nociceptive fibers to the cerebral cortex, increasing the release of endorphins both in the center and in the periphery.
Tavola n.7
Research has assigned an interesting role of β-endorphinic analgesic agent derived from T lymphocytes. When a peripheral inflammation was induced in rats, with the introduction of an antigen, β-endorphin increased in inflamed tissues, while its contents decreased in the lymph nodes. The researchers propose a mechanism by which, under normal conditions, the T lymphocytes that produce β-endorphin are transferred through the blood and lymph nodes; when inflammation occurs, lymphocytes are sequestered in inflamed tissues where they secrete β-endorphin. The importance of this observation lies in the potential for a specific opioid control of peripheral analgesia through a targeted release of β-endorphin in the sites of inflammation. Therefore β-endorphin could be considered as a mediator of the immune system of pain and stress. Further studies have shown that β-endorphin can also exert an anti-inflammatory action through its ability to alter the state of cytokine secretion from T-helper lymphocytes. The low energy density laser stimulates the production of T lymphocytes with relative release of β-endorphin.
Tavola n.8 - The neurobiology of pain
Understanding the adaptability of pain and analgesia exhibited in different painful states can advance therapies for the two main types of pain, neuropathic pain and inflammation, in which nerve and tissue damage leads to alterations both at the central level that at the peripheral level. At the peripheral nerve level, drugs acting on particular calcium channels can only target pain-related activity. Agents acting on some peripheral pain mediators can control peripheral nervous activity. We have a new generation of non-steroidal anti-inflammatory drugs, cyclo-oxygenase 2 inhibitors, that do not have gastric actions. In the spinal cord, the release of peptides and glutamates causes the activation of multiple receptors, in particular, the N-methyl-D-aspartate receptor for glutamate, which, together with other spinal systems, generates spinal hypersensitivity. One of the approaches is to block the generation of excitability, but also to increase the inhibition can also induce analgesia. The actions of the opioid, induced by the Laser, are implemented through pre-synaptic and post-synaptic inhibitory effects on central and peripheral C terminus fibers, neuro spinal, and supraspinal mechanisms (gate control system). At the same time, the role of substance P in inflammation of nervous origin has been clearly demonstrated. The peptide causes a degranulation of the mast cells and consequent release of histamine, vasodilatation and decantation of plasma with consequent release of other algogenic substances (bradykinin, serotonin) and activation of other inflammatory cells (macrophages, monocytes, to lymphocytes). The Laser blocks the inflammatory cascade, favoring a clear inversion of the inflammatory process. Moreover, always the Laser, causes a displacement of the intracellular calcium (Ca ++) in the sarcoplasm, increases the Na + K + ATPase pump with relative relaxation of the smooth muscle and muscle relaxant on the skeletal one accelerating the return to the working and sport activity.
Tavola n.9
The pheriferal jungle. Receptors located on the primary afferent fibers and their links between nerve and non-nerve derivations
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The spinal mechanisms of nociception have been studied extensively. The detailed characteristics of the Spinal cord neurons involved in the transmission of painful messages have been described as segmental and supraspinal mechanisms that can modulate information to the brain (gate control theory). Unfortunately, as in the periphery, the back horns of the spinal cord contain many identifiers and putative transmitters and receptors, including: several peptides (substance P, the peptide that releases the calcitonin gene, somatostatin, neuropeptide Y, and galanine); excitatory amino acids (aspartate, glutamate); inhibitory amino acids (y aminobytiric acid = Gaba, and glycine); nitric oxide; arachidonic acid metabolites; endogenous opioids; adenosine; monoamine oxidase). This list indicates that there are several therapeutic possibilities for the pharmacological control of the transmission of nociceptive information to the brain. The figure highlights other possible (targets) at the level of the spinal cord for the control of the transmission of nociceptive stimuli. These include amino butyric acid (GABA) systems, cholecystokinin antagonists, inhibitors of endogenous opioid degrading enzymes, and agonists that act on opioid receptors. The figure also shows the implication of the downhill pathway that use serotonin and noradrenaline in nociceptive control. Many experimental work has shown that Serotonin is very important in pain. The laser acts both on the back horns of the spinal cord and on the gelatinous gelinosa substance of Rolando, blocking the substance P preventing, in cascade, the release of the algogenic substances listed above, and favoring the release of endorphins
Tavola n.10
The 808nm infrared GaAs diode laser. it is a non-invasive method and is recognized as an additional standard treatment to improve the restoration of the functionality of patients with peripheral and muscular skeletal nerve injuries. Our experience indicates that the low energy density laser accelerates the healing processes and allows a faster return to sports competitions.
Tavola n.11
The last conclusion comes in the form of an exhortation from the master Hippocrates who urges the doctors, who are preparing for the exercise of the profession, to two fundamental objectives to be pursued. The first is to not create any harm to the person with the therapy to be implemented and, second, not to cause injuries that could affect the mental and physical integrity of the patient.
Tavola n.12
Doctors do not cure the body with the body alone, but with soul and wisdom.
