Indução de empiema em ratos através da inoculação pleural de bactérias

Abstract

Objective: to evaluate empyema formation in rats through the injection of two bacteria (Pasteurella multocida and Staphylococcus aureus), using a simple, easy-to-use surgical technique.Methods: twenty four anesthetized Wistar white rats, 250-300g in weight, submitted to right anterior thoracotomy, muscular retraction and injection of a 0.2ml solution into pleural space according the following scheme: Group I (n=12): injection of 10 10 Pasteurella multocida cultured in brain heart infusion broth. Group II (n=8): injection of 10 10 Staphylococcus aureus cultured in brain heart infusion broth. Group III (n=4): injection of bacterium-free brain heart infusion (control). The rats were sacrificed after seven days, and pleural reaction was assessed by macroscopy. Mortality, and intrathoracic liquid volume were evaluated, and bacteriological tests were also performed.Results: Seven rats died within the first 48 hours in Group I (Pasteurella multocida); five completed the experiment, but none of them presented empyema. Only one animal died within the first 24 hours in Group II (Staphylococcus aureus); seven (88%) presented empyema at the time of sacrifice. All animals survived in Group III (control), without empyema or thoracic abnormalities. Pleural inoculation of Staphylococcus aureus (Group II) was significantly associated with empyema formation (P<0.001). In this group, the amount of pleural liquid ranged from 0.9 to 3.9ml.Conclusion: It is possible to induce empyema in rats through Staphylococcus aureus pleural injection by a simple surgical technique. Differently from other experiments, the pleural injection of Pasteurella multocida did not provoke empyema in rats.J Pediatr (Rio J) 2001; 77 (6): 469-74: pleural diseases, Staphylococcus aureus, Pasteurella multocida. ResumoObjetivo: avaliar a indução experimental de empiema em ratos, através da inoculação intrapleural de duas bactérias (Pasteurella multocida e Staphylococcus aureus), utilizando técnica cirúrgica simples e de fácil execução.Métodos: foram utilizados 24 ratos albinos da raça Wistar, de ambos os sexos, pesando entre 250 e 300g, que, após a anestesia geral, foram submetidos à toracotomia anterior direita, afastamento da musculatura e inoculação de 0,2ml de solução, conforme descrição a seguir: grupo I (n=12), inoculação de Pasteurella multocida, 10 10 unidades formadoras de colônia/ml cultivados em caldo cére-bro-coração; grupo II (n=8), inoculação de Staphylococcus aureus, 10 10 unidades formadoras de colônia/ml cultivados em caldo cére-bro-coração; e grupo III (n=4), inoculação de caldo cérebro-coração estéril (controle). Os animais foram sacrificados em até 7 dias, e a intensidade da reação pleural analisada macroscopicamente conforme escala padronizada. Também foram avaliados a mortalidade, o volume de líquido na cavidade pleural e o exame bacteriológico (animais mortos e líquido pleural).Resultados: no grupo I (Pasteurella multocida), sete ratos morreram nas primeiras 48 horas de experimento. Cinco ratos foram sacrificados no período progra...

Transforming growth factor beta1 (TGF-ß1) levels in a rat model of induced pleural empyema

“…In the early 2000s, several experimental studies [6][7][8]10,[16][17][18] were conducted to correlate the presence of cytokines in pleural fluid with early detection of empyema or its associated complications. The need to use a low-cost, more accessible and reproducible alternative led us to select and adapt a previously developed rat model 11,12 to evaluate the levels of TGF-ß1 at different moments after induction of pleural effusion.…”

“…Most experimental models of pleural effusion or empyema described in the literature have employed pigs [6][7][8] or rabbits 9,10 . However, a new rat model of empyema has been successfully developed 11,12 , with greater reproducibility and lower cost and housing infrastructure than those of rabbits or pigs.…”

Tumor necrosis factor alpha in experimental empyema thoracis

“…Early studies conducted in guinea pigs or rabbits were limited by the need for sophisticated thoracotomy equipment and ventilatory support, as well as by the high mortality rate of animals 3–5. More recently, rabbit and rat models of thoracentesis‐induced empyema using different inocula have resulted in lower morbidity and mortality,6–8 so that more recent studies were able to evaluate inflammatory response with a focus on the establishment of significant relationships for clinical practice 9–13…”