Effects of different protocols of low-level laser therapy on collagen deposition in wound healing

Abstract The low-level laser has proven successful in stimulating the production of collagen in wound healing assays. However, diversity has been observed in the protocols used. This work has evaluated the effects of three protocols of low-level laser therapy (LLLT) in the healing of open wounds in rats. Standard-sized wounds of 1 cm2 were performed with a scalpel in the middorsal region of 60 male Wistar rats weighing 225±25 g, and they were assigned into four groups (n=15): CTR (non-irradiated animals), LT1 (20 J/cm2 daily), LT2 (16 J/cm2 daily) and LT3 (20 J/cm2 daily). After 7, 14 and 21 days, five animals/day were euthanized and the wounds analyzed histologically. Data were subjected to normality analysis of distribution using Shapiro-Wilk test. Gaussian data were analyzed using ANOVA and Bonferroni tests whereas non-Gaussian data were analyzed using Kruskal-Wallis and Dunn tests, considering significant p values less than 0.05. The LLLT in all protocols reduced the inflammation and collagen deposition increased significantly (p<0.05). However, LT2 showed the highest levels of collagen in all phases of the study (p<0.05) induced faster replacement of immature collagen III by mature collagen I in the early stages of repair and early collagen remodeling promoted by providing better organization architectural beams deposited. It was concluded that all protocols induced an increase in collagen scar. However, the protocol 2 (16 J /cm2, daily application) promoted the most significant increases in collagen deposition, accelerated maturation of collagen and showed the best architecture of the final fibrous scarring.

Resumo O laser de baixa potência provou ter sucesso em estimular a produção de colágeno em ensaios de cicatrização de feridas. Entretanto, grande diversidade tem sido observada nos protocolos utilizados. Este trabalho avaliou os efeitos de três protocolos de Terapia a Laser de Baixa Potência (TLBP) na cicatrização de feridas abertas em ratos. Feridas padronizadas com 1 cm2 de tamanho foram realizadas com um bisturi na região do dorso de 60 ratos Wistar machos pesando 225±25g, e foram divididos em quatro grupos (n=15): CTR (animais não irradiados), LT1 (20 J/cm2 diariamente), LT2 (16 J/cm2 diariamente) e LT3 (20 J/cm2 diariamente). Após 7, 14 e 21 dias, cinco animais/dia foram eutanasiados e as feridas analisadas histologicamente. Os dados foram submetidos à análise de normalidade da distribuição pelo teste de Shapiro-Wilk. Os dados gaussianos foram analisados pelos testes ANOVA e Bonferroni, enquanto que os dados não Gaussianos foram analisados pelos testes de Kruskal-Wallis e Dunn, considerando-se valores p significativos menores que 0,05. A TLBP em todos os protocolos reduziu a inflamação e aumentou significativamente a deposição de colágeno (p<0,05). Entretanto, LT2 apresentou os maiores níveis de colágeno em todas as fases do estudo (p<0,05), induzindo a substituição mais rápida do colágeno imaturo III pelo colágeno maduro I nos estágios iniciais de reparo e remodelação precoce do colágeno promovida por melhor organização dos feixes depositados. Concluiu-se que todos os protocolos induziram aumento da cicatriz de colágeno. Entretanto, o protocolo 2 (16 J/cm2, aplicação diária) promoveu os aumentos mais significativos na deposição de colágeno, acelerou a maturação do colágeno e apresentou a melhor arquitetura da cicatriz fibrosa final.

Effects of the essential oil of Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm. on healing and tissue repair after partial Achilles tenotomy in rats

Abstract Purpose: To investigate the cellular response to injury, analyzing histopathologic changes associated with increased cellularity, degeneration and disorganization of collagen fibers. Methods: Thirty wistar rats were divided in two groups after partial Achilles tenotomy: the right hind paw were treated with the essential oil of Alpinia zerumbet (EOAz), diluted to 33% (0.3 mL kg-1), and the left hind paw received sunflower oil for 3, 14, 30 and 90 days. Statistical significance was determined using a Chi-square and Pearson Correlation qualitative variables test. Moreover, Mann-Whitney U-test test for comparison between different groups of the same cell, one-way ANOVA, and Tukey's test of quantitative measurement. Results: A decrease hyperemia (p < 0.001) was observed in the acute phase of inflammatory cell number (p < 0.001), whereas sub-acute phase was marked by significant correlation with macrophages in fibroblasts (r = 0.17, p = 0.03), with probable induction a dense and modeled tissue. At chronic phase, it was found an increase in the number of fibroblasts and a higher percentage of type I collagen fibers (78%) compared with control collagen fibers (55%). Conclusion: Oil of Alpinia zerumbet stimulated the process of maturation, organization and tissue repair which gave it greater resistance.

Immunohistochemical profile of stromal constituents and lymphoid cells over the course of wound healing in murine model

PURPOSE: To assess the evolution profile of the immunohistochemical expression of stromal constituents over the time-course of wound healing in a murine model. METHODS: Surgical wounds were performed in the back of 24 Wistar rats. After three, seven, 14 and 21 days, six rats were euthanized and the wounded histologically processed to assess the immunohistochemical expression of CD3, CD20, CD31, α-SMA and type-I collagen. Non-injured skin samples (NSS) were used as control. Data were subjected to statistical analysis using ANOVA and Tukey test. RESULTS: The mean of CD3 and CD20 positive cells in the wounds was significantly higher than in NSS at seven and 14 days (p<0.001). The blood vessels content was significantly lower than in NSS (p<0.05) at three days, but increased at seven and 14 days (p<0.01). The mean of α-SMA positive cells at seven, 14 and 21 days was higher than in NSS (p<0.05). The relative content of type I collagen increased from three to 21 days, but remained lower than in NSS (p<0.05). CONCLUSIONS: Lymphoid cells, myofibroblasts and microvessels contents varied over the time-course of wound healing, with peak at seven days and progressive reduction until 21 days. The type I collagen content increased over time. .

Chemopreventive effect of Brazilian green propolis on experimental dermal carcinogenesis in murine model / Efecto quimiopreventivo del propóleos verde brasileño sobre la carcinogénesis cutánea en el modelo murino experimental

The aim of this study was to assess the effect of oral administration of Hydroalcoholic Extract of Green Propolis (HEGP) on dermal carcinogenesis in rodent model. For the biological assay, we used 36 mice, assigned into 6 groups (n=6): CTR (treated with 100 mg/kg HEGP and no tumor induction), TUM (treated with water and tumor induction), GP10 (treated with 10 mg/kg HEGP and tumor induction), GP50 (treated with 50 mg/kg HEGP and tumor induction) and GP100 (treated with 100 mg/kg HEGP and tumor induction). Cancer induction was performed in the back of the mice by topical application of DMBA. After 16 weeks, mice were euthanized and their backs were submitted to post-mortem histological analysis. The mean number of lesions developed in TUM (4.14±0.89) was significantly higher than in GP10 (2.05±1.02), GP50 (1.8±1.92) and GP100 (2.5±1.73) (p<0.05). The tumors formed in HEGP-treated groups were histologically more differentiated, but only in PV100 in situ lesions were evidenced. Infiltration of anatomical noble structures was less frequent in HEGP-treated groups (p<0.05). Our data suggest that oral administration of HEGP provided partial inhibition of DMBA-induced dermal carcinogenesis, as well as appeared to modulate the differentiation and infiltrative potential of the carcinomas in rodent model.

El objetivo de este estudio fue evaluar el efecto de la administración oral de extracto hidroalcohólico del propóleos verde (HEGP) sobre la carcinogénesis dérmica en modelo de roedores. Para el ensayo biológico, se utilizaron 36 ratones asignados en 6 grupos (n = 6): CTR (tratado con 100 mg/kg HEGP y sin inducción de tumores), TUM (tratada con agua e inducción de tumores), GP10 (tratado con 10 mg/kg HEGP e inducción de tumores), GP50 (tratado con 50 mg/kg HEGP e inducción de tumores) y GP100 (tratado con 100 mg/kg HEGP e inducción de tumores). La inducción de cáncer se llevó a cabo en la región dorsal de los ratones por aplicación tópica de DMBA. Después de 16 semanas, los ratones fueron sacrificados y sus dorsos fueron sometidos a análisis histológico post-mortem. El número medio de lesiones desarrolladas en TUM (4,14±0,89) fue significativamente mayor que GP10 (2,05±1,02), GP50 (1,8±1,92) y gp100 (2,5±1,73) (p<0,05). Los tumores formados en grupos tratados con HEGP fueron histológicamente más diferenciados, pero sólo en PV100 las lesiones in situ fueron manifiestas. La infiltración de las estructuras anatómicas blanco fue menos frecuente en los grupos tratados con HEGP (p<0,05). Nuestros datos sugieren que la administración oral de HEGP proporciona una inhibición parcial de la carcinogénesis dérmica inducida por DMBA, así como pareció modular la diferenciación y potencial infiltrante de los carcinomas en el modelo animal.

Modulatory activity of brazilian red propolis on chemically induced dermal carcinogenesis

To evaluate modulatory effects of a hydroalcoholic extract of Brazilian red propolis (HERP) on dermal carcinogenesis using a murine model. METHODS: The HERP was used at concentrations of 10, 50 and 100 mg/kg (PROP10, PROP50 and PROP100, respectively) to modulate dermal carcinogenesis induced by the application of 9,10-dimetil-1,2-benzatraceno (DMBA) on the backs of animals. RESULTS: The chemical compounds identified in HERP included propyl gallate, catechin, epicatechin and formononetin. PROP100 treatment resulted in significantly decreased tumor multiplicity throughout the five weeks of tumor promotion (p<0.05), and this concentration also resulted in the highest frequency of verrucous tumors (p<0.05). All of the tumors that developed in DMBA-treated animals were regarded as squamous cell carcinomas and were either diagnosed as non-invasive verrucous carcinomas or invasive squamous cell carcinomas (SCCs). The average score for malignancy was significantly lower in the PROP100-treated group than the non-treated group (p<0.05), but there was no difference between the other groups (p>0.05). CONCLUSION: The oral administration of hydroalcoholic extract of Brazilian red propolis at a dose of 100 mg/kg had a significant modulatory effect on the formation, differentiation and progression of chemically induced squamous cell carcinoma in a murine experimental model.

Evaluation of wound healing activity of atranorin, a lichen secondary metabolite, on rodents

The aim of this study was to investigate the wound healing activity of atranorin cream (Patent requested) on excision wounds. Seventy-two male rats were anesthetized and an excisional wound was performed. Then the rats were randomly assigned into three groups: untreated control group; atranorin 1 (group treated with 1% AT ointment); and atranorin 5 (group treated with 5% AT ointment). Six animals of each group were euthanized 3, 7, 14 or 21 days after surgical procedures and the wounded areas were analyzed and removed. Serial histological sections were obtained and stained by histochemical techniques (Hematoxilin-Eosin-HEand Sirius red) and immunohistochemical techniques. Topical application of atranorin reduced wound areas, induced earlier granulation tissue formation, increased cell proliferation, improved collagenization and modulated the myofibroblasts differentiation when compared to control animals. It is suggested that atranorin modulates the wound healing process. These data suggest that this formulation based on atranorin extracted from Cladina kalbii AHTI may be a new biotechnological product for wound healing clinical applications.

Assessment of antimicrobial activity and healing potential of mucous secretion of Achatina fulica / Evaluación de la actividad antimicrobiana y la cicatrización potencial de la secreción mucosa de Achatina fulica

Achatina fulica's secretion has been recently related to antibacterial, antifungal, and cicatricial properties, and it is influenced by the kind of food offered. Therefore, this study investigated the healing potential of dressing films based on mucous secretion of Achatina fulica. Thus, surgical wounds performed in black wistar rats were dressed with films based on collagen, and on mucous secretion of A. fulica fed with Lactuca sativa; undresses worked as wounds control. After 3, 7, 14 and 21 days the animals were euthanized, and the wounds were microscopically evaluated. On the 3rd and 7th days dressing films based on mucus provided acceleration of the formation maturation of granulation tissue, better epithelization rates, and more rapid replacement of type III for type I collagen fibers. On the 14th and 21st days, these dressings induced more intense deposition and better architectural disposition of type I collagen fibers, and hastened the regeneration of cutaneous phaneros. Dressings obtained from A. fulica fed with Lactuca sativa provided the most expressive results. This study suggests that films produced with mucous secretion of A. fulica can be successfully employed as wound dressing, particularly if snails are fed with Lactuca sativa.

A la secreción mucoproteica del Achatina fulica se le han asignado propiedades antibacterianas, antifúngicas y cicatriciales que pueden estar influidas por el tipo de alimento que se ofrece a este especimen. Este estudio investigó el potencial curativo de películas basadas en la secreción mucosa de Achatina fulica alimentaba con diferentes tipos de plantas. Fueron tratadas heridas provocadas en el dorso de ratas Wistar con películas de colágeno y películas realizadas a partir de la secreción mucosa de A. fulica, alimentados con plantas de lechuga (L. sativa), utilizando como parámetro de comparación la curación del grupo de control. Después de 3, 7, 14 y 21 días los animales fueron sacrificados y las heridas fueron evaluadas microscópicamente. En los días 3 y 7, las heridas tratadas con moco mostraron mejores tasas de formación y maduración del tejido de granulación, epitelización, y más rápido recambio de colágeno tipos III y I. A los días 14 y 21, hubo una intensa deposición del colágeno tipo I y aceleración en la regeneración de la piel. Los resultados obtenidos a partir de A. fulica alimentados con plantas de lechuga (L. sativa) mostraron mejores resultados. Este estudio sugiere que las películas producidas con secreción mucosa de A. fulica pueden ser utilizadas con éxito como apósito, especialmente si los caracoles se alimentan con plantas de lechuga L. sativa.