Effects of renal dysfunction on healing of colonic anastomosis: experimental study in wistar rats / Efeitos da disfunção renal na cicatrização de anastomoses colônicas: estudo experimental em ratos wistar

ABSTRACT Background: Chronic kidney disease affects more than 500 million people worldwide. In this context, the uremic toxins present are related to worsening in tissue healing. Aim: Evaluate on healing of colonic anastomosis in uremic rats, serum and anatomopathological indicators, which may be related to the change tissue repair process. Methods: Twenty Wistar rats, were randomly separated into two groups. In the sham group they were submitted to 5/6 nephrectomy simulation in left kidney, simulation right nephrectomy, median laparotomy, colotomy and colorraphy. In the uremia group, they were submitted to 5/6 nephrectomy of the left kidney, total nephrectomy of the right kidney and median laparotomy, colotomy and colorraphy. Were collected for serum urea, creatinine and CRP dosages and the colonic segments were studied for evaluation of granulation tissue, collagen maturation, microvascular and myofibroblasts density, and cell viability. Through histochemical processing, microvascular density was evaluated by anti-CD34 monoclonal antibody marking, cell viability by cell proliferation nuclear antigen screening and myofibroblasts density with monoclonal anti-α-actin antibody. Computerized histometry was used for evaluations of collagens type I and III by the coloration of picrosirius. Results: The group submitted to nephrectomy 5/6, compared to the sham group, show urea increase (p<0.0000) and higher C reactive protein (p=0.0142). Decrease of granulation tissue formation (border reepithelialization p=0,0196, angiofibroblast proliferation p=0.0379), mean collagen I (p=0,0009) and collagen III (p=0,016), microvascular density (p=0,0074), cell proliferation nuclear antigen (p<0,0000) and myofibroblasts (p<0,0001). Conclusion: The uremia induced by nephrectomy 5/6 model establishes negative impact in the colonic wound healing.

RESUMO Racional: A doença renal crônica atinge mais de 500 milhões de pessoas em todo o mundo. Neste contexto, as toxinas urêmicas estão relacionadas ao comprometimento da cicatrização tecidual. Objetivo: Avaliar, na cicatrização de anastomoses colônicas de ratos urêmicos indicadores séricos e anatomopatológicos que possam estar relacionados com alteração do processo de reparação tissular. Métodos: Utilizaram-se 20 ratos Wistar divididos aleatoriamente em dois grupos. No grupo simulação eles foram submetidos à simulação da nefrectomia 5/6 do rim esquerdo, simulação de nefrectomia total do rim direito, laparotomia mediana, colotomia e colorrafia. No grupo uremia, eles foram submetidos à nefrectomia 5/6 do rim esquerdo, nefrectomia total do rim direito, laparotomia mediana, colotomia e colorrafia. Coletaram-se amostras de sangue para dosagens séricas da ureia, creatinina e proteína C reativa, e do cólon para processamentos histológicos e histoquímicos na avaliação do tecido de granulação, maturação de colágeno, densidade microvascular e de miofibroblastos, viabilidade celular cicatricial. Empregou-se a histometria computadorizada para as avaliações de colágenos tipos I e III, densidade microvascular pela marcação com anticorpo monoclonal anti-CD34, viabilidade celular pela pesquisa do antígeno nuclear de proliferação celular e a densidade de miofibroblastos com anticorpo monoclonal anti-α-actina. Resultados: O grupo submetido à nefrectomia 5/6, em comparação ao grupo simulação, demonstraram aumentos da ureia sérica (p<0,0000) e proteína C reativa (p=0,0142), redução da formação de tecido de granulação (reepitelização de bordas p=0,0196, proliferação angiofibroblástica p=0,0379), porcentagens de colágeno I (p=0,0009) e colágeno III (p=0,016), densidade microvascular (p=0,0074) e miofibroblastos (p<0,0001) e antígeno nuclear de proliferação celular (p<0,0000). Conclusão: A uremia induzida pelo modelo de nefrectomia 5/6 determina impacto negativo no processo de cicatrização colônico.

Amniotic membrane as a biological dressing in infected wound healing in rabbits

PURPOSE: To investigate amniotic membrane as a biological dressing in infected wound healing in rabbits. METHODS: The use of preserved amniotic membranes (AMs) was examined using 15 rabbits with experimentally induced wound infections on their backs. Healing was histologically evaluated during different phases including inflammation, granulation, epithelialization, and fibroplasia. The animals were distributed into three groups for histological study at seven, 14, 21, and 28 days post-wound induction. Group A did not receive treatment: the wound was left exposed and dry; Group B received a daily exposure treatment with collagenase; and Group C received one AM, which also remained exposed. RESULTS: A marked reduction of the inflammatory phase was observed in Group C at 21 days, and the granulation phase of this healing increased at 14 days. Epithelialization was similar among the three groups, and fibroplasia was more pronounced in Group C at 14 days. Furthermore, gradual collagen organization also began for the animals in Group B at 14 days. CONCLUSION: The amniotic membrane did not significantly alter the inflammation, epithelialization, or fibroplasia phases but did increase angiogenesis up to Day 14 compared with the dry dressing and collagenase treatments. .

Biologia da reparaçäo tecidual / Biology of tissue repair

O processo inflamatório é multimediado através de manifestaçöes locais, do sistema nervoso e do sistema hormonal. A inflamaçäo é um processo fisiológico que precede o processo de reparaçäo propriamente dito. Abordam-se além, dos fatores humorais e celulares que medeiam a inflamaçäo, a dinâmica do processo de reparaçäo