VIP verbessert die mikrovaskuläre Perfusion des Dünndarms nach Ischämie und Reperfusion der Leber
Background: The present study investigates the effects of the vasoactive hormone VIP (vasoactive intestinale polypeptide) on the microcapillary perfusion of the small intestine after hepatic ischemia and reperfusion in the rat model. Method: Wistar rats underwent laparotomy under ether-anaesthesia and continuous hemodynamic monitoring. By clamping the left A. hepatica hepatic ischemia was induced for a period of 40 min followed by 60 min of reperfusion. The control group was prepared in a similar fashion without clamping of liver vessels. Ten minutes before starting reperfusion, VIP (50 pmol/kg/h) was continuously infused intravenously. Microcirculatory parameters as functional capillary density (FCD [cm-1]), both in the mucosa as well as in the muscularis, red blood cell velocity (RBCV [mm/s]) and perfusion index (PI) were determined for the small intestine using intravital microscopy (plasma stain: FITC-Dextran). Significant differences were evaluated using the Tukey’s test after performing a multivariance-analysis (ANOVA).
Results: (mean ± SEM) The FCD of the small intestine following ischemia and reperfusion of the left hepatic lobe (I/R group) showed a significant reduction in comparison with the control group in both the mucosa (I/R 515 ± 20 vs. control 770 ± 18 [cm-1]; p < 0.01) and the muscularis (I/R 272 ± 9 vs. control 320 ± 5 [cm−1];p < 0.01). In parallel, the PI was significantly decreased (I/R 0.68 ± 0.025 vs. control 0.93 ± 0.013; p < 0.01). The RBCV was significantly lower in the I/R group than in the control group (I/R 0.35 ± 0.007 vs. control 0.49 ± 0.013 [mm/s]; p < 0.01). After giving VIP there was an increase of the FCD in the mucosa (615 ± 21 [cm−1]) and of the RBCV (0,43 ± 0,013 [mm/s]). GRP only supplied an increase of the RBCV (0,39 ±0,01 [mm/s]). Conclusion: This present intravital microscopic study supports the hypothesis that the protection of intestinal functions appears to be of importance in hepatobiliary surgery. The changes in microvascular perfusion of the small intestine are possibly responsible for increased postoperative resorption of enterotoxins as well as for septic complications. In cases of extended periods of ischemia we suggest that vasoactive substances like VIP in addition to preoperative preparation of the intestine could improve microvascular perfusion.
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