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Intestinal mucosal oxidative damage and bacterial translocation in cirrhotic rats
Maite Chiva1, Carlos Guarner, Carmen Peralta
1Liver Section, Department of Gastroenterology, Hospital de la Santa Creu i Sant Pau, Sant Antoni M Claret 167, 08025 Barcelona, Spain.
Background:
Bacterial translocation plays an important role in the pathogenesis of spontaneous bacterial peritonitis mainly due to intestinal bacterial overgrowth. Alterations in the functional integrity of the intestinal barrier caused by an increased production of free radical metabolites as a consequence of portal hypertension could also facilitate bacterial translocation in cirrhotic rats.
Objective:
The aim of the study was to determine intestinal mucosal lipid peroxidation and neutrophil infiltration and their relationship with portal hypertension and bacterial translocation in cirrhotic rats.
Design:
Eighteen male Sprague-Dawley rats with cirrhosis induced by carbon tetrachloride, administered by gavage, and eight control rats were included in the study.
Methods:
Samples of jejunum, ileum and caecum were obtained by laparotomy for the determination of malondialdehyde and myeloperoxidase as indexes of lipid peroxidation and neutrophil infiltration, respectively. Samples of ascitic and pleural fluids, mesenteric lymph nodes and ileal stools were obtained for the culture of microoganisms.
Results:
The concentration of malondialdehyde was significantly higher in ileal and caecal, but not in jejunal mucosa, in cirrhotic rats, mainly in those with ascites (P< 0.01), as compared to control rats (P< 0.01), and in cirrhotic rats with bacterial translocation compared to those without bacterial translocation (P< 0.01). No differences between groups were observed in the concentrations of myeloperoxidase in jejunum, ileum or caecum. A direct correlation between ileal malondialdehyde and portal pressure was observed (P< 0.01).
Conclusions:
Cirrhotic rats, particularly those with ascites and bacterial translocation, show increased malondialdehyde levels in ileal and caecal mucosa. These results suggest that mucosal oxidative damage in ileum and caecum could favour bacterial translocation in cirrhotic rats.
Insights
Increased oxidative damage in the ileum and cecum of cirrhotic rats, indicated by higher malondialdehyde levels, may promote bacterial translocation, especially in those with ascites.
Area of Science:
- Gastroenterology
- Hepatology
- Pathophysiology
Background:
- Bacterial translocation contributes to spontaneous bacterial peritonitis in cirrhosis, often linked to intestinal bacterial overgrowth.
- Portal hypertension in cirrhotic rats may impair intestinal barrier integrity, increasing susceptibility to bacterial translocation.
Purpose of the Study:
- To investigate intestinal mucosal lipid peroxidation and neutrophil infiltration in cirrhotic rats.
- To determine the relationship between these markers, portal hypertension, and bacterial translocation.
Main Methods:
- Cirrhosis was induced in male Sprague-Dawley rats using carbon tetrachloride.
- Malondialdehyde (lipid peroxidation) and myeloperoxidase (neutrophil infiltration) were measured in jejunum, ileum, and cecum.
- Microbial cultures were performed on ascitic fluid, lymph nodes, and stools.
Main Results:
- Higher malondialdehyde levels were observed in the ileal and caecal mucosa of cirrhotic rats, particularly those with ascites and bacterial translocation.
- No significant differences in myeloperoxidase levels were found between groups.
- A direct correlation existed between ileal malondialdehyde and portal pressure.
Conclusions:
- Cirrhotic rats exhibit elevated malondialdehyde in the ileal and caecal mucosa, especially with ascites and bacterial translocation.
- These findings suggest that oxidative damage in the intestinal mucosa contributes to bacterial translocation in cirrhosis.