Gastric proliferative lesions induced by duodenogastric reflux in rats

Abstract

Purpose: To analyze mucosal proliferation and its characteristics, through specific models of duodenogastric reflux, in the stomach of Wistar rats. Methods: Seventy-five healthy and adult male rats were divided into three groups: group Icontrol (n = 25 animals), submitted to gastrotomy of the posterior wall of the glandular stomach; group II -DGR (n = 25 animals), submitted to duodenogastric reflux through latero-lateral gastrojejunal anastomosis in the posterior wall of the glandular stomach and group III -DGR-P (n = 25 animals), submitted to duodenogastric reflux through the pylorus following the same procedure of group II, sectioning and closing the afferent loop. The animals were observed during 36 weeks and subsequently the mucosal lesions were analyzed, with macroscopic and microscopic examination of the prepyloric, the gastrojejunostomy and the squamous area of the stomach. Results: Group I did not present any kind of lesion. Macroscopic lesions of the prepyloric area in groups II and III were 0% and 20%, respectively. Macroscopic lesions of the gastrojejunal stoma in groups II and III were 36% and 88%, respectively, and 12% and 28%, respectively, in the squamous area. Microscopically, adenomatous hyperplasia (AH), squamous hyperplasia (SH) and adenocarcinoma (AC) were diagnosed. The occurrence of AH at the prepyloric area in groups II and III was 0% and 40%, respectively, and in the gastrojejunal stoma, 40% and 72%, respectively. The occurrence of SH in the squamous area in groups II and III was 12% and 20%, respectively, without statistical differences between the groups. AC was found only in three animals of groups III (12%). Conclusions: The duodenogastric reflux in this experimental model caused high frequency of proliferative lesions of the gastrojejunal stoma and in the prepyloric area, while adenocarcinoma was a rare occurrence. Key words: Duodenogastric Reflux. Hyperplasia. Adenocarcinoma. Rats. RESUMOObjetivo: Avaliar as lesões proliferativas que se desenvolvem na mucosa gástrica de ratos Wistar após modelo específico de refluxo duodeno-gástrico. Métodos: Foram utilizados 75 ratos adultos machos divididos em três grupos experimentais: o grupo I (controle) submetido a gastrotomia na parede posterior do estômago glandular (25 animais); o grupo II (RDG), foi submetido a gastrojejunoanastomose látero-lateral na parede posterior do estômago glandular (25 animais) e o grupo III (RDG-P) submetido a gastrojejunoanastomose látero-lateral na parede posterior do estômago glandular, com secção e fechamento da alça (25 animais). Os animais foram observados durante 36 semanas, após o que foram realizados estudos macroscópicos e microscópicos da anastomose gastrojejunal, da região pré-pilórica e região escamosa do estômago. Resultados: Os animais do Grupo I não apresentaram nenhum tipo de lesão. No grupo II observou-se 40% de lesões do tipo hiperplasia adenomatosa na anastomose e 12% de hiperplasia escamosa. No grupo III obteve-se 40% de hiperplasia adenomatosa na mucosa pré-pilórica, 72 % de hiperplas...

Correlation of precancerous lesion incidence with duodenogastric reflux and N-nitroso compound duration at reflux and antireflux stomach surgery: An experimental study

“…The specific finding in our study is the incidence of such a large percentage of cancer and dysplastic changes in the B2 group (conditionally refluxed) after 24 weeks of the experiment, since the time of DGR and MNNG action is relatively short, compared to other researchers, where the timelines of the experiments were 40, 90 and even 120 weeks [22][23][24][25][26] . These results suggest that the time of influence of DGR in the presence of MNNG is in direct correlation with the severity of precancerous lesions and that the minimum time of the occurrence of cancer is 20 weeks after the start of the experiment.…”

Omeprazole and adenocarcinoma in the stomach of rats submitted to duodenogastric reflux. Is there a protective effect?

“…The study included 120 male Wistar rats, with approximately 8 weeks and weight between 180 and 280 grams. The induction of gastric duodenal reflux was obtained through a surgical procedure, as previously described 9,10,18 .…”

“…Group III (DGR-P) -Forty animals were submitted to gastrojejunoanastomosis similar to group II, but with section and ligation of the afferent loop, inducing retrograde duodenogastric reflux by the pylorus (Fig. 3) 9,10,18 . After the procedures, the animals ingested only water during the initial 24 hours after surgery and free access to the feed after this period.…”

“…The animals were weighed weekly, during the observation period and euthanized after 16 weeks, with the same anesthetic procedure. Obtaining the surgical specimen and analyzing the macroscopic changes found followed a previous research protocol, described by Monteiro et al 18 .…”

“…The protocol for the histological analysis was prepared, including the following criteria 11,15,18 : Squamous Hyperplasia (SH) -Squamous epithelium thicker than normal twice or more, with hyperkeratosis.…”