Clinical and histological responses to laparoscopically-induced peritonitis in rats

Abstract

Purpose:To evaluate the efficacy of inducing peritonitis in rats through laparoscopic cecal ligation (CL), by means of an elastic band. Methods: Twelve Wistar rats were subjected to cecal ligated with an elastic band applied using a specially constructed applicator. In six of the animals (the CL group) the cecal sac was preserved intact whilst in the remaining animals (the CLP group) the sac was perforated with scissors. Clinical parameters, characteristics of the peritoneal cavity and cecum, and histological features of the cecal tissue were observed in all experimental animals 8 and 24 h after surgery. Results: CLP animals exhibited at least one clinical sign of sepsis within the first 8 h of observation. The peritoneal liquid was observed to be clear in almost all members of the CLP. Polymorphonucleated cells were detected in the tunica serosa of the cecum of CLP animals. In contrast, all members of the CL group were alive after 24h, and of polymorphonucleated cells in the muscle layer of the cecal wall were observed. The presence of peritoneal liquid was not detected in CL animals. Conclusion: Although elastic ligation of the cecum was reproducible, puncture of the cecal sac was essential for induction of sepsis. Key words: Models, Animal. Peritonitis. Laparoscopy. Rats. RESUMOObjetivo: Avaliar a eficácia de induzir peritonite em ratos através da ligadura cecal laparoscópica (CL), por meio de banda elástica. Métodos: Doze ratos Wistar foram submetidos a ligadura cecal com banda elástica aplicada com dispositivo especialmente construído para este fim. Em seis animais (grupo CL), a bolsa cecal foi mantida intacta, enquanto nos outros animais (grupo CLP), a bolsa foi perfurada com tesoura. Parâmetros clínicos, características da cavidade peritonial e ceco, e histologia do tecido cecal foram examinados em todos os animais 8 e 24 horas após a cirurgia. Resultados: Os animais do grupo CLP apresentaram pelo menos um sinal clínico de sepses nas primeiras 8 h de observação. Líquido peritonial claro foi observado em quase todos os membros do grupo CLP. Leucócitos polimorfonucleares foram identificados na serosa do ceco dos animais do grupo CLP. Por outro lado, todos os animais do grupo CL estavam vivos após 24 h, e leucócitos polimorfonucleares estavam restritos à muscular própria. Presença de líquido peritonial não foi detectada nos animais do grupo CL. Conclusão: A ligadura elástica do ceco foi reprodutível e a secção da bolsa cecal foi essencial para a indução de sepse. Descritores: Modelos Animais. Peritonite. Laparoscopia. Ratos.

Effects of the povidone-iodine (PVPI) in treatment of bacterial peritonitis induced in rats

“…The model more used is the ligation and puncture of the cecum, that have the advantage of promoting similar pathophysiology of the secondary peritonitis in human beings, with peritoneal irritation, necrosis, presence of great amount of citokines and continuous leak of intestinal content to abdomen 12 . However, it can present great variability of responses, once the inflammatory response and the mortality depends on the diameter of the cecal perforation.…”

Does Helium Pneumoperitoneum Reduce the Hyperinflammatory Response in Septic Animals during Laparoscopy?

“…Prior to surgery, all animals received a single intramuscular dose (30 mg/kg) of the antibiotic ceftriaxone (Rocephin; Roche, Rio de Janeiro, RJ, Brazil), and were subsequently anesthetized by intramuscular injection of a mixture of ketamine (40 mg/kg; Cristália Produtos Químicos e Farmacêuticos, Itapira, SP, Brazil) and xylazine (8 mg/kg; Schering-Plough, Cotia, SP, Brazil). Animals in groups SLC and SLH were submitted to laparoscopy with 15 min insufflation with either carbon dioxide or helium, as appropriate, in order to expose the cecum and allow CLP to be performed according to standard techniques ( Figure 1) [22]. Animals in groups CLC and CLH were submitted to identical procedures except that no CLP was performed.…”