Wound healing - A literature review.

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.

Wound healing - A literature review

Abstract: 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.

Influence of the HPA axis on the inflammatory response in cutaneous wounds with the use of 670-nm laser photobiomodulation.

This study evaluated the influence of hypothalamic-pituitary-adrenal (HPA) axis in cutaneous wounds subjected to laser biomodulation. A total of 48 rats were divided into two groups: Group I (GI) with 24 adrenalectomized animals and Group II (GII) with 24 non-adrenalectomized animals. Each group was divided into two subgroups: the irradiated subgroup which laser was applied to four points at the edges of the wound (670 nm laser, 9 mW) and control subgroup. Rats in each subgroup were sacrificed at 24 or 72 h. Adrenal glands were only removed from GI rats. Three days after adrenalectomy, a cutaneous wound was made. An immunohistochemical analysis was performed using anti-CD45 and anti-CD8 antibodies. Flow cytometry was used to count T lymphocytes and their subpopulations in blood. Decreases in the number of CD45-positive inflammatory cells and in the total numbers of CD8- and CD45-positive cells were observed in histological sections of adrenalectomized animals subjected to laser biomodulation at 24h. Similar results were observed for distribution of total lymphocytes in blood (p<0.05). The action of 670 nm laser does not depend exclusively on HPA axis. It is believed that corticosteroid-promoting enzymes liberated in non-adrenal tissues may influence immune response under the influence of this type of phototherapy.

Dynamics of Capillaria-hepatica-induced hepatic septal fibrosis in rats.

INTRODUCTION: The pathogenesis of septal hepatic fibrosis, induced in rats by Capillaria hepatica infection, was studied with the aid of a large collection of stored paraffin blocks, representative of the different evolutive phases of fibrosis which appeared in 100% of infected rats. METHODS: Studies were conducted involving histology, immunohistochemistry, immunofluorescence and morphometric methods, in order to observe the dynamic behavior of the cellular and matrix components of fibrosis, over a one year period of evolution. RESULTS: Observation verified that septal fibrosis originates from several portal spaces simultaneously. Its origin and progression involve blood vessel proliferation (angiogenesis), multiplication of actin-positive cells (pericytes and myofibroblasts) and progressive collagen deposition. By the end of 4-5 months, a progressive decrease in all these components was observed, when signs of regression of septal fibrosis became more evident over time. CONCLUSIONS: Besides indicating the fundamental role played by angiogenesis in the pathogenesis of fibrosis, these morphological data concerning the dynamics of this C. hepatica experimental model proved to be adequate for future investigations regarding the functional aspects of fibrosis induction, progression and regression.

Dynamics of Capillaria-hepatica-induced hepatic septal fibrosis in rats / Dinâmica da fibrose septal hepática induzida por Capillaria hepatica em ratos

INTRODUCTION: The pathogenesis of septal hepatic fibrosis, induced in rats by Capillaria hepatica infection, was studied with the aid of a large collection of stored paraffin blocks, representative of the different evolutive phases of fibrosis which appeared in 100 percent of infected rats. METHODS: Studies were conducted involving histology, immunohistochemistry, immunofluorescence and morphometric methods, in order to observe the dynamic behavior of the cellular and matrix components of fibrosis, over a one year period of evolution. RESULTS: Observation verified that septal fibrosis originates from several portal spaces simultaneously. Its origin and progression involve blood vessel proliferation (angiogenesis), multiplication of actin-positive cells (pericytes and myofibroblasts) and progressive collagen deposition. By the end of 4-5 months, a progressive decrease in all these components was observed, when signs of regression of septal fibrosis became more evident over time. CONCLUSIONS: Besides indicating the fundamental role played by angiogenesis in the pathogenesis of fibrosis, these morphological data concerning the dynamics of this C. hepatica experimental model proved to be adequate for future investigations regarding the functional aspects of fibrosis induction, progression and regression.

INTRODUÇÃO: Um extenso material de patologia experimental arquivado em blocos de parafina, ilustrativo das diferentes fases da fibrose hepática septal, que 100 por cento dos ratos desenvolvem em seguida uma infecção com o nematódeo Capillaria hepatica. MÉTODOS: O material foi sistematicamente estudado com métodos morfológicos e morfométricos, no sentido de se verificar o comportamento dos elementos celulares e matriciais durante a evolução da fibrose hepática septal ao longo de um período de um ano. RESULTADOS: Foi constatado que a fibrose septal se origina de vários espaços porta ao mesmo tempo, com proliferação vascular (angiogênese), multiplicação de células actino-positivas (pericitos, miofibroblastas) e progressivo depósito de colágeno. Ao fim dos 4-5 meses há uma involução regressiva de todos estes indícios morfológicos, mas com alguns septos persistindo bem evidentes até o fim de um ano. CONCLUSÕES: Além de ilustrar o papel fundamental desempenhado pela angiogênese, o modelo se mostrou adequado para futuros estudos funcionais relacionados com a indução, progressão e regressão da fibrose hepática.

Capillaria hepatica-induced septal fibrosis in rats: a contribution to the study of liver fibrogenesis.

INTRODUCTION: Septal fibrosis of the liver regularly develops in rats infected with the nematode Capillaria hepatica. Curative treatment of the infection prevents the development of septal fibrosis when intervention occurs up to postinfection day (PID) 15, but not later. The present investigation aimed to demonstrate which parasitic factors are present when the process of septal fibrosis can no longer be prevented by curative treatment. METHODS: Wistar rats were infected with 600 embryonated eggs of C. hepatica administered by gavage and treated with ivermectin and mebendazole in separate groups at PIDs 10, 12, 15, 17 or 20. Rats from each group and their nontreated controls, were killed and examined 40 days after the end of treatment. RESULTS: Findings by PID 15 were compatible with the stage of complete maturation of infection, when worms and eggs were fully developed and a complex host-parasite multifocal necroinflammatory reaction showed greater intensity, but with no signs of septal fibrosis, which appeared from PID 17 onward. CONCLUSIONS: Since the worms spontaneously died by PID 15, not only septal fibrosis production, but also its maintenance and further development appeared dependent on the presence of eggs, which were the only parasitic factor remaining thereafter.

Capillaria hepatica-induced septal fibrosis in rats: a contribution to the study of liver fibrogenesis / Contribuição para o estudo da fibrogenesis hepática em ratos infectados com Capillaria hepatica

INTRODUCTION: Septal fibrosis of the liver regularly develops in rats infected with the nematode Capillaria hepatica. Curative treatment of the infection prevents the development of septal fibrosis when intervention occurs up to postinfection day (PID) 15, but not later. The present investigation aimed to demonstrate which parasitic factors are present when the process of septal fibrosis can no longer be prevented by curative treatment. METHODS: Wistar rats were infected with 600 embryonated eggs of C. hepatica administered by gavage and treated with ivermectin and mebendazole in separate groups at PIDs 10, 12, 15, 17 or 20. Rats from each group and their nontreated controls, were killed and examined 40 days after the end of treatment. RESULTS: Findings by PID 15 were compatible with the stage of complete maturation of infection, when worms and eggs were fully developed and a complex host-parasite multifocal necroinflammatory reaction showed greater intensity, but with no signs of septal fibrosis, which appeared from PID 17 onward. CONCLUSIONS: Since the worms spontaneously died by PID 15, not only septal fibrosis production, but also its maintenance and further development appeared dependent on the presence of eggs, which were the only parasitic factor remaining thereafter.

INTRODUÇÃO: A fibrose septal do fígado se desenvolve regularmente em ratos infectados pelo nematódeo Capillaria hepatica. O tratamento curativo da infecção, feito antes do 15º dia da infecção, mas não mais tarde, impediu o aparecimento da fibrose septal. O presente trabalho procura verificar qual o estado do parasitismo aos 15 dias da infecção, crucial para patogenia da fibrose septal. MÉTODOS: Ratos foram infectados por via digestiva com 600 ovos embrionados de C. hepatica e tratados com Ivermectina e mebendazol, em grupos separados, aos 10, 12, 15, 17 ou 20 dias após a infecção. O animal de cada grupo e seus respectivos controles foram mortos e examinados aos 40 dias após o fim do tratamento. RESULTADOS: Os achados aos 15 dias da infecção mostraram a maturação completa da parasitose, com presença de ovos e vermes, circundados por reação necro-inflamatória, mas ainda sem fibrose septal. Daí por diante, a fibrose septal se fez presente. CONCLUSÕES: Como os vermes morrem espontaneamente após o 15º dia da infecção, não apenas a origem, mas o posterior crescimento e a manutenção da fibrose septal dependem da presença dos ovos acumulados no fígado, os quais são os únicos elementos parasitários presentes após o 15º dia da infecção por C. hepatica no rato.

In vitro and in vivo experimental models for drug screening and development for Chagas disease.

Chagas disease, a neglected illness, affects nearly 12-14 million people in endemic areas of Latin America. Although the occurrence of acute cases sharply has declined due to Southern Cone Initiative efforts to control vector transmission, there still remain serious challenges, including the maintenance of sustainable public policies for Chagas disease control and the urgent need for better drugs to treat chagasic patients. Since the introduction of benznidazole and nifurtimox approximately 40 years ago, many natural and synthetic compounds have been assayed against Trypanosoma cruzi, yet only a few compounds have advanced to clinical trials. This reflects, at least in part, the lack of consensus regarding appropriate in vitro and in vivo screening protocols as well as the lack of biomarkers for treating parasitaemia. The development of more effective drugs requires (i) the identification and validation of parasite targets, (ii) compounds to be screened against the targets or the whole parasite and (iii) a panel of minimum standardised procedures to advance leading compounds to clinical trials. This third aim was the topic of the workshop entitled Experimental Models in Drug Screening and Development for Chagas Disease, held in Rio de Janeiro, Brazil, on the 25th and 26th of November 2008 by the Fiocruz Program for Research and Technological Development on Chagas Disease and Drugs for Neglected Diseases Initiative. During the meeting, the minimum steps, requirements and decision gates for the determination of the efficacy of novel drugs for T. cruzi control were evaluated by interdisciplinary experts and an in vitro and in vivo flowchart was designed to serve as a general and standardised protocol for screening potential drugs for the treatment of Chagas disease.

In vitro and in vivo experimental models for drug screening and development for Chagas disease

Chagas disease, a neglected illness, affects nearly 12-14 million people in endemic areas of Latin America. Although the occurrence of acute cases sharply has declined due to Southern Cone Initiative efforts to control vector transmission, there still remain serious challenges, including the maintenance of sustainable public policies for Chagas disease control and the urgent need for better drugs to treat chagasic patients. Since the introduction of benznidazole and nifurtimox approximately 40 years ago, many natural and synthetic compounds have been assayed against Trypanosoma cruzi, yet only a few compounds have advanced to clinical trials. This reflects, at least in part, the lack of consensus regarding appropriate in vitro and in vivo screening protocols as well as the lack of biomarkers for treating parasitaemia. The development of more effective drugs requires (i) the identification and validation of parasite targets, (ii) compounds to be screened against the targets or the whole parasite and (iii) a panel of minimum standardised procedures to advance leading compounds to clinical trials. This third aim was the topic of the workshop entitled Experimental Models in Drug Screening and Development for Chagas Disease, held in Rio de Janeiro, Brazil, on the 25th and 26th of November 2008 by the Fiocruz Program for Research and Technological Development on Chagas Disease and Drugs for Neglected Diseases Initiative. During the meeting, the minimum steps, requirements and decision gates for the determination of the efficacy of novel drugs for T. cruzi control were evaluated by interdisciplinary experts and an in vitro and in vivo flowchart was designed to serve as a general and standardised protocol for screening potential drugs for the treatment of Chagas disease.

Influence of 670 nm low-level laser therapy on mast cells and vascular response of cutaneous injuries.

Laser biomodulation has been getting considerable attention when it comes to its effects on the inflammatory process. Its action upon mast cells have been already studied, but none of the previous papers related the resulting effect to the inflammatory and vascular status of the wounds. Therefore, the acute inflammatory process as well as the mast cells behavior and the vascular response were analyzed under the influence of laser treatment on cutaneous wounds. Surgical procedures were performed on 60 rats divided into sham and laser groups. Low-level laser therapy was performed following surgical procedures (670 nm, 9 mW, 4 J/cm(2), 124 s). Histological specimens were analyzed for cell morphology and immunohistochemistry using anti-von Willebrand Factor and anti-Vascular Endothelial Growth Factor antibody. Laser treatment resulted in an increased acute inflammatory response in irradiated tissues; surgical wounds treated with laser therapy had increased polymorphonuclear cells, mast cells and vasodilation and lower numbers of vessels than those in control rats. Laser treatment resulted in higher expression of VEGF in irradiated tissues 6-24h post-treatment (p=0.002). It is possible to observe an amplification of acute inflammatory process during the first hours after surgical procedure in rats submitted to laser therapy.

Sobre a contribuição para o estudo da anatomia patológica da moléstia de Carlos Chagas / About the contribution to the study of the pathology of Chagas disease

Revisões históricas aos avanços científicos para o controle da doença, o Simpósio Internacional Comemorativo do Centenário da Descoberta da Doença de Chagas (1909-2009).

Morbidity due to Schistosoma mansoni--Entamoeba histolytica coinfection in hamsters (Mesocricetus auratus).

Data on Schistosoma mansoni-Entamoeba histolytica coinfection are scarce in the literature. In the present study, hamsters that had been infected for 70 days with Schistosoma mansoni (LE strain) were inoculated via the portal vein with two strains of trophozoites of Entamoeba histolytica: ICB-EGG (highly virulent) and ICB-RPS (non-virulent). The most evident result of coinfection was increased morbidity and mortality, in comparison with either of the infections alone. Histologically, there were no evident signs of interaction between these two infections. The morphological findings of schistosomal granuloma and amoebic abscesses in the liver were similar to those seen in the respective single-infection controls. However, there was severe wasting of the animals with both infections and greater numbers of amoebic lesions in their livers. The results obtained indicated that schistosomiasis aggravates the course of amoebiasis in hamsters.

Morbidity due to Schistosoma mansoni - Entamoeba histolytica coinfection in hamsters (Mesocricetus auratus)

Data on Schistosoma mansoni-Entamoeba histolytica coinfection are scarce in the literature. In the present study, hamsters that had been infected for 70 days with Schistosoma mansoni (LE strain) were inoculated via the portal vein with two strains of trophozoites of Entamoeba histolytica: ICB-EGG (highly virulent) and ICB-RPS (non-virulent). The most evident result of coinfection was increased morbidity and mortality, in comparison with either of the infections alone. Histologically, there were no evident signs of interaction between these two infections. The morphological findings of schistosomal granuloma and amoebic abscesses in the liver were similar to those seen in the respective single-infection controls. However, there was severe wasting of the animals with both infections and greater numbers of amoebic lesions in their livers. The results obtained indicated that schistosomiasis aggravates the course of amoebiasis in hamsters.

Dados sobre a co-infecção Schistosoma mansoni-Entamoeba histolytica são escassos na literatura. No presente estudo, hamsters com 70 dias de infecção por Schistosoma mansoni (cepa LE) foram inoculados com trofozoítos de Entamoeba histolytica, cepa ICB-EGG (virulenta) e cepa ICB-RPS (não virulenta), via veia porta. O mais evidente resultado da co-infecção foi o aumento da morbidade e mortalidade, quando comparado com os animais com somente uma das infecções. Histologicamente, não houve sinais evidentes da interação entre as duas infecções. O aspecto morfológico do granuloma esquistossomótico e do abcesso hepático amebiano são similares aos observados nos controles, com somente uma infecção. Entretanto, foi observado que os animais co-infectados apresentavam-se mais debilitados e com maior número de lesões amebianas no fígado. Os resultados obtidos indicam que a esquistossomose agrava o curso da infecção amebiana em hamsters.

As relações entre álcool e fibrose hepática / Relations Between Alcohol and Liver Fibrosis

O álcool exerce uma ação tóxica direta sobre as células hepáticas, podendo resultar em uma lenta e progressivaformação de fibrose. Contudo, toda fibrose é passível de ser degradada, uma vez sua causa sendo eliminada.Atualmente, está demonstrado que até a fibrose de uma cirrose é reversível, com desaparecimento de toda a sintomatologia associada. Deve ser ressaltado que, nos casos mais avançados, lesões associadas (vasculares, metabólicas, etc) podem permitir uma evolução progressiva e independente dos mecanismos patogênicos, a despeito da remoção do agente causal inicial.

The influence of low-level laser therapy on biomodulation of collagen and elastic fibers

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 interferência 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 Gálio-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 significância 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.

The influence of low-level laser therapy on biomodulation of collagen and elastic fibers.

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/cm(2) exhibited more expressive results than that with 8 J/cm(2). 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.

Aspectos morfológicos dos autotransplantes de tireóide da rata / Morphologic aspects of thyroid autotransplantion in the female rat

Foram operadas cinquenta ratas Wistar, adultas, separadas em seis grupos: 1, 2, 3, grupos isolado 1 e 2 e um grupo piloto. O lobo esquerdo da tireóide da rata foi dividido em três fragmentos similares e implantados no músculo esternoclidomastóideo, na raiz do mesentério e no ovário. Os tecidos implantados foram examinados histologicamente após dez, vinte e trinta dias. No grupo isolado 1, depois de trinta dias a porção restante da tireóide in situ foi removida, passando a viver somente com os implantes. Para verificar aspectos funcionais, foram implantados três fragmentos da tireóide em um grupo isolado na raiz do mesentério. T3, T4 e TSH foram dosados no soro antes e após a retirada da tireóide. O exame histológico mostrou que o tecido tireóideo implantado sofria inicialmente discreta hipotrofia, retornando em seguida para os limites da normalidade. Os melhores resultados foram obtidos com o implante no mesentério. Os valores de T3 e T4 eram baixos e os de TSH altos. Apoiado nos resultados histológicos e hormonais, concluiu-se que no período estudado, a tireóide autotransplantada manteve sua arquitetura folicular, cumprindo a função de produzir os hormônios

The murine "air pouch" model: a sequential morphologic study of its formation

Light and electron microscopy coupled to Laser scanning confocal microscopy and immunohistology (for adhesion detection, revealed that in its development, the air pouch produced in mice, starts as a traumatic event in where is produced a subcutaneous air space surrounded by compressed pre-existing connective issue. It soon matures toward a well circunscribed air pouch, acquiring an epithelial-looking lining suported by newly synthesized connective tissue layers. We recognized three developmental stages and considered they should be taken in account in experimental designs making use of the air pouch model. The capability of the air pouch lining to express adhesion molecules, its easy manipulation and its situation as an isolated comportament turns the air pouch a good alternative model to the coelomatic cavities.