ABSTRACT
BACKGROUND:The intestine is not only the main target attacked by sepsis but also the vital organ which mediated sepsis. The recovery of the damaged intestinal barrier structure and function is related to the occurrence and outcome of multiple organ dysfunction syndrome (MODS). How to protect and reduce the damage of the intestinal mucosa and how to promote the reconstruction of the intestinal mucosa have been the important topics in sepsis for many years. This study aimed to investigate the influential factors of intestinal mucosal reconstruction after intestinal epithelial injuryin vivo in a mouse model of sepsis.METHODS:Mice were subjected to cecal ligation and puncture (CLP) for induction of sepsis to assess intestinal mucosal damage, epithelial cell apoptosis, and transformed number of goblet cells, and to detect the concentration of TNF-α, IL-1 and TGF-β1 and TFF3 (trefoil factor 3) expression in the small intestinal mucosa. All above were performed by HE staining, western blot, ELISA and immunohistochemistry respectively. The experimental animals were divided into a sepsis group and a sham-operation group. The animals with sepsis were separately killed at 6 (7 animals), 24 (7 animals) and 48 hours (7 animals) after CLP.RESULTS:Injured intestinal mucosa was observed in the 3 groups under a light microscope, in which damage scores in the 24-hour and 48-hour groups were higher than in the 6-hour group and no difference was found between the two groups. Moreover, less of goblet cells or other epithelial cells adjacent to the injured surface migrated into the wound to cover the denuded area. The number of goblet cells was substantially decreased in the three CLP groups compared with the sham-operation group. Protein levels of IL-1 and TNF-α were significantly increased by 3-4 fold at all time points when compared with the sham-operation group, and cleaved caspase-3 by 4 fold. Although TFF3 expression was modestly increased for 6 hours after the onset of CLP, it appeared to decline at 24 hours and 48 hours as shown by Western blot. A similar tendency was observed upon TGF-β1, i.e. the protein level was not elevated at 24 hours and 48 hours, but increased modestly at 6 hours.CONCLUSIONS:Sepsis from CLP shows less restitution on the surface of injured intestinal mucosa. There is evidence that both constant inflammatory reaction and epithelial cell apoptosis may affect mucosal reestablishment of the intestine at the onset of sepsis. Mucosa after severe sepsis showed the state of high inflammation, and declined goblet cell function and mucosal reconstruction, which affected the repair of damaged intestinal barrier. Constant inflammatory reaction, and declined goblet cell function and mucosal reconstruction ability may affect the reestablishment of intestinal mucosa at the onset of sepsis.
ABSTRACT
ObjectiveTo investigate the unfavorable factors of intestinal mucosa repair after the intestinal epithelial injury in vivo in a mouse model of sepsis. MethodsThe method of cecal ligature and puncture (CLP) was used to induce sepsis and then the intestinal mucosa damage, epithelial cell apoptosis and the number of transformed goblet cells were observed, and the concentrations of serum TNF-αt, IL-1 and TGF-β1 and TFF3 ( trefoil factor 3) in small intestinal mucosa were determined. All above various laboratory examinations were made by different assays including H-E staining, western blot, ELISA and immunohistochemistry respectively. The experimental mice were divided into sepsis group and sham operation control group. The mice with sepsis were separately sacrificed 6 hours ( n = 7 ), 24 hours ( n = 7) and 48 hours ( n = 7) after CLP. Results In septic mice group, the injured intestinal mucosa was found 6 hours after CLP. The damage scores in mice 24 h and 48 h after CLP were higher than those 6 h after CLP, but there was no significant difference between those 24 h and 48 h after CLP. Moreover, a few goblet cells or other epithelial cells adjacent to the injured surface migrated onto the wound to cover the denuded area. The number of goblet cells was substantially decreased in mice of sepsis group 6 hours after CLP compared with sham operation control group. Compared with sham operation control group, levels of IL-1 and TNF-α significantly increased 3-4 times in mice of sepsis group at all intervals, and the phosphorylated caspase-3 increased 4 times. Although TFF3 assayed by using Western blot showed modest increase 6 h after CLP and it declined 24 h and 48 h later. A similar change was found in TGF-β1, it modestly increased 6h after CLP, but it didn't elevate 24 h and 48 h later. ConclusionsSevere sepsis keeps on the inflammatory reaction and epithelial cell apoptosis, preventing the repair of intestinal mucosa from injury.