Der Einfluss von Zinkmangel auf die Wundheilung in der ECM des Rattendarms

Abstract

Introduction: As an integral part of more than 200 enzymes, zinc has a strong impact on cellular metabolism, immune function, hormonal regulation, and wound healing. The influence of a zinc deficiency on the wound healing of intestinal anastomosis is not yet clear, though the epidemiological rate of intestinal operations as well as the percentage of zinc deficiency, both, increase age-related. Thus, this study investigates the impact of controlled zinc deficiency on the healing of colonic anastomosis in rat model. Material und methods: 40 Wistar-rats received a controlled feeding in a single cage husbandry for 21 days. 20 animals were fed with a zinc deficient diet, 20 animals served as an ordinary fed control group. Zinc deficiency was controlled by a hair analysis using the atomic absorption spectral photometry. The zinc content of the undernourished animals fell below the measurements of the control group (p = 0,004). At the end of the feeding period, the animals were randomized and divided into 4 groups. Group 1 (n = 7) and 2 (n = 12) served as a control, group 3 (n = 8) und 4 (n = 8) as zinc deficient specimen. In group 1 und 3, a typical circular colonic anastomosis was performed. Group 2 and 4 underwent an anti-mesenteric colotomy with suture closure. The feeding was maintained postoperatively. On day 7, all anastomoses were explanted. Measurements included the villous configuration, the expression of MMP 2, 8, 9, and 13, the collagen ratio I/III, the expression β-catenin, c-myc, and notch3, the proliferation rate (Ki67) and the rate of apoptosis (TUNEL). Statistics included the Kruskal-Wallis-test and the Mann-Whitney-U-test. P < 0,05 was regarded as significant. Results: MMP 2, 9, and 13 measured significantly higher in the zinc deficient groups. Reciprocally, the collagen I/III ratio measured significantly higher in the control groups. C-myc demonstrated a significant lower expression after zinc deprivation, whereas ß-catenin and notch3 revealed a higher expression but no significance. The proliferation score only tended to result in lower measurements, whereas the villous configuration, MMP 8, und the rate of apoptosis were not influenced by the zinc deficiency. Conclusion: A zinc deficiency significantly increases the expression of several MMPs, thus reducing the collagen I/III ratio. Accompanied by significantly lower levels of c-myc, zinc deficiency decreases the quality of wound healing.