Effects of aging on abdominal wall healing in rats

Abstract

Purpose:The aim of this study was to assess abdominal wall healing in old and young adult rats. Methods: On average, young animals were 110 days old and old animals were 762 days old. A 4.0 cm median laparotomy was performed under anesthesia, followed by laparorrhaphy on two synthesis planes, i.e. peritoneum-muscle-aponeurosis and skin, using continuous 5.0 nylon sutures. The animals were evaluated on the 3 rd , 7 th , 14 th and 21 st postoperative days. The resistance of the two planes was studied separately and a histopathologic analysis was performed on sections stained with hematoxylineosin and Sirius Red. Immunohistochemical analysis was also carried out using PCNA, LCA and CD34. Results: The skin scars gained resistance in a similar manner at the initial time points, but those of young rats were more resistant on the 21 st day (p=0.0029). Total and type III collagen content was similar in the two groups and type I collagen content was higher in young animals on the 14 th day. Inflammatory cell infiltration was more marked in the skin wounds of young animals on the 3 rd day (p=0.0190). Reepithelialization was similar and angiogenesis was more intense in the skin wounds of young animals on the 14 th day (p=0.0062). The peritoneum-muscle-aponeurosis wounds gained similar resistance during the early phases, but were more resistant on the 14 th day (p=0.0005) and on the 21 st day (p=0.0023) in old rats Collagen concentration was higher in the wounds of old animals on the 3 rd day (p=0.0112) and in the wounds of young animals on the 21 st day (p=0.0348). The inflammatory reaction was more intense in the wounds of old animals on the 3 rd day (p=0.0060) and angiogenesis was more intense on the 14 th day (0.0432). Conclusion: Although there are some differences in the healing course between young and old animals, age, of itself, does not impair the healing of abdominal wall wounds in rats. Key words: Wound healing. Aging. Abdominal wall. Rats. RESUMOObjetivo: Estudar a cicatrização da parede abdominal em ratos adultos jovens e velhos. Métodos: Os ratos adultos jovens tinham em média 110 dias de idade e os velhos 762 dias. Uma laparotomia mediana de 4,0 cm foi feita sob anestesia, seguida de laparorrafia com 2 planos de síntese, isto é, peritônio-músculo-aponevrose e pele, com síntese contínua de fio de náilon 5.0. Os animais foram avaliados com 3, 7, 14 e 21 dias de pós-operatório. A resistência dos dois planos foi avaliada separadamente e a análise histológica feita em cortes preparados pela Hematoxilina-eosina e Sirius red. Análise imunohistoquímica foi realizada empregando PCNA, LCA and CD34. Resultados: A cicatriz da pele ganhou resistência de modo similar nos tempos iniciais, mas as dos animais jovens foram mais resistentes no 21º dia (p=0.0029). A densidade de colágeno total e tipo III foi similar nos dois grupos, porém o colágeno tipo I mostrou-se mais denso nas cicatrizes dos animais jovens no 14.º dia. O infiltrado de células inflamatórias foi maior nas cicatrizes dos animais jovens no 3.º dia (p=...

Abdominal wall healing in reoperated rats

“…The healing study of muscleaponeurotic tissue in terms of collagen concentration has not received the deserved attention either. The researchers apply more time and resources studying the skin tissue because rejuvenation treatments have been considered of extreme importance lately 4 . The goal of the current study is to experimentally evaluate abdominal wall healing, in reoperations at the same surgical site, by means of macroscopic analysis, histological and breaking strength studies of the surgical scar.…”