Page 32 - Veterinary Laser Therapy in Small Animal Practice

18 Veterinary Laser Therapy in Small Animal Practice

(a) (b)

Figure 3.4 A similar situation to Figure 3.3 treated using the same parameters. (a) Wound inflammation and dehiscence 10 days
after adenoma surgery. (b) Just one treatment was enough to reverse the situation. This picture was taken 72 h later.

also with in vivo experimental models of, for example, increases this response. [49–52] But an excessive amount
chronic nerve compression, [39] myocardial infarc- of ROS production is damaging to the organs, even
tion, [40] acute joint inflammation, [41] acute muscle fatal, as seen in septic shock and systemic inflammatory
injury, [42] wound healing, [43] asthma and pleurisy [44, 45] , response syndrome (SIRS).
among others. The deleterious and distant effects of With NO, regulation is also complicated and still
these mediators, such as smooth airway muscle dys- raises some questions: NO is central to cardiovascu-
function, [46] can also be decreased with LT. lar homeostasis, neurotransmission, and the immune
When the inflammatory cascade begins, the body response, but its oxidized metabolites are toxic and
also releases anti-inflammatory cytokines, such as contribute to inflammation and oncogenesis. NO was
IL-4 and IL-10, which inhibit the production of pro-in- named “molecule of the year” in 1992 by the journal
flammatory cytokines by macrophages and induce Science, and more and more roles are still being discov-
lymphocyte apoptosis, and TGF-β, which inhibits lym- ered and investigated, for example in insulin-resistance
phoid cell proliferation but promotes multiplication and neurodegenerative diseases. NO can also react with
of fibroblasts, osteoblasts, and smooth muscle cells. O to form reactive nitrogen species (RNS), which are
2
Other anti-inflammatory mechanisms include cytokine produced by macrophages as part of the non-specific
inhibitors, such as IL-1RA, which block the cascade, or antimicrobial cytotoxic response, but these can turn
at least attenuate the intensity or duration of the phe- into nitrates, nitrites, and eventually, carcinogenic
nomena. Infrared light may also contribute to this shift nitrosamines. So the effect of NO at any given moment
from inflammation to repair, increasing the expression may vary in a sort of a bimodal way, depending on the
of anti-inflammatory cytokines in asthma models, [45] amount and source, among other things. It sounds a bit
tendinitis, [47] wound healing, [48] and arthritis models. [41] crazy, but that is one of the wonders of how a living
organism works.
3.1.5 Molecule of the year and more NO is synthesized by nitric oxide synthase (NOS).
NOS can be isolated in almost any tissue, but the neu-
A final, heterogeneous group includes other molecules, ronal (nNOS) and endothelial (eNOS) isoforms are
like reactive oxygen species (ROS), nitric oxide (NO), expressed constitutively, while the inducible (iNOS)
and carbon monoxide (CO). These are some of the isoform is expressed by cells like leukocytes in response
most intricately regulated molecules. For instance, an to bacterial lipopolysaccharides or pro-inflammatory
increase in ROS production can help neutrophils fight cytokines. The cardiovascular effects of NO include
microbes better (actually, the respiratory burst they endothelium-dependent vascular relaxation and inhi-
experience is oxygen-dependent; they need about 50 bition of platelet aggregation, among others. The
times more oxygen in those circumstances!), and LT isoform iNOS can generate large amounts of NO for

REDONDO PRINT (4-COL BLEED).indd 18 08/08/2019 09:47