Regeneration and tissue repair processes consist of a sequence of molecular and cellular events which occur after the onset of a tissue lesion in order to restore the damaged tissue. The exsudative, proliferative, and extracellular matrix remodeling phases are sequential events that occur through the integration of dynamic processes involving soluble mediators, blood cells, and parenchymal cells. Exsudative phenomena that take place after injury contribute to the development of tissue edema. The proliferative stage seeks to reduce the area of tissue injury by contracting myofibroblasts and fibroplasia. At this stage, angiogenesis and reepithelialization processes can still be observed. Endothelial cells are able to differentiate into mesenchymal components, and this difference appears to be finely orchestrated by a set of signaling proteins that have been studied in the literature. This pathway is known as Hedgehog. The purpose of this review is to describe the various cellular and molecular aspects involved in the skin healing process.

Laser therapy reduced the inflammatory reaction, induced increased collagen deposition and a greater proliferation of myofibroblasts in experimental cutaneous wounds.

The study of low-level laser therapy upon extracellular matrix elements is important to understand the wound healing process under this agent. However, little is known about the interference of laser light in relation to collagen and elastic fibers. Cutaneous wounds were performed on the back of 72 Wistar rats and a Ga-Al-As low-level laser was punctually applied with different energy densities. The animals were killed after 24, 48, 72 hours and 5, 7 and 14 days. Tissues were stained with hematoxilin-eosin, sirius red fast green and orcein and then analyzed. It was observed that the treated group exhibited larger reduction of edema and inflammatory infiltrate. The treated animals presented a larger expression of collagen and elastic fibers, although without statistical significance (p > 0.05). Treatment with a dosage of 4 J/cm² exhibited more expressive results than that with 8 J/cm². In this study, the authors concluded that low-level laser therapy contributed to a larger expression of collagen and elastic fibers during the early phases of the wound healing process. DESCRIPTORS:Lasers; Laser therapy, low-level; Wound healing; Collagen. RESUMO:O estudo da terapia a laser de baixa densidade de energia sobre os diversos constituintes da matriz extracelular é crucial para o entendimento do processo cicatricial sob esse agente. Todavia, pouco se sabe sobre a interferên-cia do laser em relação às fibras colágenas e elásticas. Realizaram-se ferimentos cutâneos padronizados no dorso de setenta e dois ratos Wistar e, em seguida, aplicação pontual do raio laser de baixa potência do tipo Arseneto de Gá-lio-Alumínio (Ga-Al-As) com diferentes densidades de energia. Os animais foram sacrificados com 24, 48 e 72 horas e aos 5, 7 e 14 dias. Procedeu-se à análise das secções teciduais coradas por hematoxilina-eosina, sírius vermelho e orceína. Observou-se, que nos grupos submetidos à terapia a laser, houve maior redução do edema e infiltrado inflamatório. Os animais tratados apresentaram uma maior expressão de fibras colágenas e elásticas, embora sem significân-cia estatística (p > 0,05). No tratamento com a fluência de 4 J/cm² observaram-se melhores resultados do que naquele em que foi utilizada a fluência de 8 J/cm². Neste estudo, pôde-se concluir que o laser contribuiu para uma maior expressão de fibras colágenas e elásticas durante o processo cicatricial. DESCRITORES:Lasers; Terapia a laser de baixa intensidade; Cicatrização de feridas; Colágeno.

No abstract

No abstract

LLLT alone accelerates post-surgical tissue repair and reduces edema and the polymorphonuclear infiltrate even in the presence of dexamethasone.

Nonsyndromic cleft lip with or without cleft palate (NSCL ± P) is the most common orofacial birth defect, exhibiting variable prevalence around the world, often attributed to ethnic and environmental differences. Linkage analyses and genome-wide association studies have identified several genomic susceptibility regions for NSCL ± P, mostly in European-derived or Asian populations. Genetic predisposition to NSCL ± P is ethnicity-dependent, and the genetic basis of susceptibility to NSCL ± P likely varies among populations. The population of Brazil is highly admixed, with highly variable ancestry; thus, the genetic determinants of NSCL ± P susceptibility may be quite different. This study tested association of 8 single-nucleotide polymorphisms (SNPs), previously identified by genome-wide studies in other populations, with NSCL ± P in a Brazilian population with high African ancestry. SNPs rs560426, rs642961, rs1530300, rs987525, rs3758249, rs7078160, rs17085106, and rs13041247 were genotyped in 293 Brazilian patients with NSCL ± P and 352 unaffected Brazilian controls. Each sample was also genotyped for 40 biallelic short insertion/deletion polymorphic markers to characterize genetic ancestry. The average African ancestry background was 31.1% for the NSCL ± P group and 36.7% for the control group. After adjustment for ancestry and multiple testing, the minor alleles of rs3758249 (OR: 1.58, 95% CI: 1.25-2.01, P = 0.0001) and rs7078160 (OR: 1.59, 95% CI: 1.21-2.07, P = 0.0002) were significantly associated with risk of NSCL ± P. Polymorphisms located in IRF6 (rs642961) and 8q24 (rs1530300 and rs987525) showed marginal associations in this Brazilian population with high African ancestry. These results indicate that rs3758249 at 9q22 and rs7078160 at 10q25.3 represent risk loci for NSCL ± P in the Brazilian population with high African ancestry.

The literature has shown that low-level laser therapy accelerates the repair of cutaneous wounds. However, there is a scarcity of scientific studies that characterise the possible systemic interference of laser photobiomodulation. The aim of this research was to quantitatively evaluate blood corticosterone levels and tissue cytokine expression in cutaneous wounds of rats treated with low-level laser therapy (semiconductor diode AsGaAl, continuous emission, 9 mW, 670 nm, 0.031 W/cm(2), beam with an output area of 0.28 cm(2)) and normal controls. A total of 36 male Wistar rats were used and randomly divided into two groups of 18 rats each. A standardised circular 6-mm-diameter wound was made in the dorsal skin region of each rat, and they were euthanised at 1, 6 and 12 h after cutaneous surgery. The blood was collected, and portions of cutaneous tissue and subcutaneous muscle were removed and cryopreserved. Corticosterone levels in the blood were measured by a radioimmunoassay technique; histological sections were submitted to the ELISA technique for analysis of tissue cytokine expression levels. At 6 h after surgery, a significant increase in corticosterone and a significant reduction in the levels of IL-1β and IL-6 in tissues of irradiated wounds were observed when compared to controls (p < 0.05). The levels of TNF-α and IL-10 expression were not significantly different between the groups at different time intervals. Thus, this study strongly suggests a systemic and local biomodulation of low-level laser therapy as indicated by the blood levels of corticosterone and the tissue expression of IL-1β and IL-6, respectively.