Iatrogenic extracellular matrix disruption as a local trigger for postoperative ileus

Abstract

Background Active MMP-9 disruption of the extracellular matrix plays an important role in inflammatory disorders. In this study, we investigated the inflammatory role of MMP-9 and the extracellular matrix (ECM) breakdown product hyaluronan as a trigger for the postoperative intestinal inflammatory response of postoperative ileus. Methods A standardized intestinal surgical manipulation (SM) was performed on rats to produce ileus assessed by the oral non-digestible FITC-dextran transit assay. Isolated intestinal muscularis extracts were studied for mRNA expressions of IL-6, MMP-9 and CD44. Peritoneal MMP-9 activity was quantified using zymography. Peritoneal fluid and serum were quantified for hyaluronan and TIMP-1 levels by ELISA. Peritoneal macrophages were cultured and exposed to peritoneal fluid or synthetic hyaluronan for ELISA analysis of IL-6 and MIP-1α. Results Transit was significantly delayed after SM and extracts of the isolated jejunal and colonic muscularis demonstrated a significant induction of IL-6, MMP-9 and CD44 mRNAs compared to controls. Zymography confirmed significant MMP-9 activity in peritoneal fluid compared to controls. ELISA measurements showed a significant upregulation in hyaluronan and TIMP-1 in the peritoneal fluid and serum. Additionally, ELISA and RT-PCR measurements of peritoneal macrophages stimulated with postsurgical peritoneal fluid and synthetic hyaluronan resulted in higher expressions of IL-6 and MIP-1α in the macrophage supernatant. Conclusions Our results confirm that MMP-9 disruption in the ECM with hyaluronan release and muscularis CD44 receptor induction has the potential to trigger muscularis proinflammatory cascades which cause postoperative ileus and we suggest that MMP-9 inhibition may be a novel therapeutic approach to limit postoperative ileus.

Electroacupuncture treatment partly promotes the recovery time of postoperative ileus by activating the vagus nerve but not regulating local inflammation

“…POI was induced by a standardized small bowel manipulation procedure7. Rats were anesthetized with inhaled isoflurane, and the abdomen was opened by midline laparotomy.…”

“…To determine the effects of IM and EA on gut motility, GI transit was measured at 6 h, 12 h and 24 h after IM as previously described7. Two hundred microliters of a liquid non-absorbable FITC-dextran (70,000 Da, Sigma-Aldrich, USA) was administered via oral gavage.…”

“…IM induced the influx of leukocytes, mainly monocytes, into the muscularis, after surgery456. Secretion of cytokines (IL-6, TNF-α) from monocytes and smooth muscle inhibitory substances (NO, COX-2) contribute to the delay in intestinal transit78. These events delay GI transit, decrease local neuromuscular function and inhibit neurogenic pathways, thereby suppressing motility along the entire gastrointestinal tract for sustained postoperative periods910.…”

Detection of Matrix Metalloproteinases by Zymography

“…They have been suggested as either diagnosis tools or therapeutic targets in a broad range of conditions such as multiple sclerosis [2,3], periodontal disease [4,5], cancer [7], rheumatoid arthritis and osteoarthritis [8,9], intestinal disease [10,11], or cardiovascular diseases [12]. The accurate and reproducible detection of different MMPs is therefore critical for both basic and translational research.…”

“…Indeed, any serum present in the culture may obscure effects from differential treatment of the cells (Fig. 2) [15,14,16,10,4,8] …”