Fachbereich Veterinärmedizin



    Standardisierung eines normothermen Hämoperfusionskreislaufes zur Vitalerhaltung eines Jejunumpräparates des Schweins als Grundlage späterer Resorptionsuntersuchungen (2016)

    Schröder-Koch, Nadine (WE 12)
    Berlin: Mensch und Buch Verlag, 2016 — 128 Seiten
    ISBN: 978-3-86387-754-5
    URL (Volltext): http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000103306
    Institut für Tierpathologie

    Robert-von-Ostertag-Str. 15
    Gebäude 12
    14163 Berlin
    +49 30 838 62450

    Abstract / Zusammenfassung

    The isolated organ perfusion is an important method to support in vitro investigations regarding fundamental research, toxicology and pharmacology as well as transplantation when looking for a supplemental procedure to bioassays. Being the main organ of the body to absorb foreign substances, the intestine becomes an important research object. Besides being the site of complex resorption procedures, it is also involved in sepsis due to it`s vulnerability in terms of an ischemia - reperfusion injury. In order to study unique physiological and pathological mechanisms of the intestine an established perfusion equipment has been modified and standardised for this study. The aim of the study was a three-hour perfusion of intestinal segments as possible without loss of function and histologically visible damage. For the present study, from 16 anesthetized pigs sections of its proximal jejunum of 150 cm length were extracted and connected to an extracorporal circulatory system. The period of warm ischemia was kept as short as possible with 12.9 ± 3.6 minutes. Blood was used as autologous perfusion medium. The animals were sacrificed by exsanguination immediately following organ removal. Due to the central denervation of the intestine small amounts of norepinephrine were added continuously with a syringe pump. The hemodynamic parameters could be read continuously and were recorded every 20 minutes. The intestine was weighed before and after the perfusion period; the post weighing was done with and without mesenterium. After termination of the experiment tissue samples from the proximal, middle and distal section of the jejunum (Vprox, Vmed, Vdist) were taken for histological evaluation. These were compared to native tissue samples of the jejunum (Kprox, Kdist) of the same animal which had not been perfused and were taken beforehand. Histological evaluation was performed regarding edemas of the intestine sections as well as the integrity of mucosa. To achieve statistic data, Wilcoxon test as non-parametrical method was chosen for two related random samples. The organ resistance declined from its initially high value at a median of 0.5 mmHg/ml/100g to a median value with ranges from 0.26 to 0.34 mmHg/ml/100g in the course of the experiment. This was correlated to oxygen consumption which in tendency increased within the first 40 minutes of the experiment to a median of 88,7 μmol/min/100g with decreasing organ resistance at the same time. Individual intestines reached peak values of 252 - 291 μmol/min/100g which was reflected in form of an almost undamaged mucosa in the results of the histological evaluation. The integrity and functionality of the intestine mucosa also showed up in the two significant increases of the glucose absorption after an application of the maltose solution and correlates to the histological results of the perfused intestines (Vprox, Vmed, Vdist) which in comparison to the control groups (Kprox, Kdist) - without damage of the mucosa (Score 0) - only showed a minimal lifting of the mucosa ephitelium from the lamina propria, by intact brushborder (Score 1). During the course of the essay the median of the lactate values ranged between 7,4 und 8,5 mg/dl/100g. In combination with the consumption of oxygen and glucose these values do also mirror the vitality of the organs. The weight examinations showed that the resulting edema was located predominantly in the mesentery (median: net weight ante perfusionem 160,8 g, net weight post perfusionem 292,7 g, net weight post perfusionem after separation of the mesentery 121,5 g). This was also reflected in the histological studies where it was found that the formation of edema of the serosa in the control groups (Kprox, Kdist) as well as in the experimental groups (Vprox, Vmed, Vdist) in median corresponded to a low level edema (score 1) and had already occurred intraoperatively. After termination of the experiment the tunica muscularis in the groups Vmed and Vprox showed an even lower formation of edema (median score 0,5) than the two control groups Kprox and Kdist (medan score 2). In addition the level of edema formation of the tela submucosa was exclusively increased in the group Vdist with a median score of 1,25 in opposition to the control groups Kprox and Kdist with a median score of 1; hence this also showed no conjunction to the executed perfusion. Since edemas occur solely perivascular it can be assumed that the fluidity of the edema especially has leaked from the non cannulated lymphatic vessels. In the control groups Kprox and Kdist, the tunica mucosa showed an edema with a median score of 0 and 0,5 and did not deteriorate because of the perfusion (Mediane: Vprox Score 0, Vmed Score 0, Vdist Score 0,5). The haemoperfused jejenum-modell established hereby is a promising basis for further research regarding intestinal resorption procedures as well as for questions
    concerning ischaemia- reperfusion damage particularly in terms of organ transplantation.