Tu1977 IL-17 Induces Hypercontractility in Intestinal Smooth Muscle Strips and Cells via Nf?B Signaling

Abstract

Introduction: Gastric emptying (GE) in rats is mostly determined after gavaging a radioactive or colored meal, with determination of the percentage of food remaining in the stomach after sacrificing the animal as a measure for gastric emptying. We hereby present a novel method to directly and continuously assess gastric emptying of a liquid meal in conscious rats without the need to sacrifice animals. Methods: After an overnight fast, 6 Wistar HAN rats were placed in a custom-made Bolmann cage to minimize movement artefacts. Rats were treated with atropine (1 mg kg-1; subcutaneous), pancreatic polypeptide (PP; 100 pmol kg-1 min-1; intravenous infusion) or vehicle (administered on 2 occasions). 15 minutes after the start of the treatment, rats were gavaged with 3 ml of a liquid test meal containing 1% hydroxypropyl methylcellulose solution and 0.5 g ml-1 BaSO4 (0 cal). The abdomen was visualized as a dorsal projection using X-ray imaging (29 kV, 40mAs; Embracemammography device; Selenia software (Hologic)). X-ray imaging was possible throughout the whole experiment. In order to estimate the test meal fraction in the stomach, X-rays were taken every 5-10 minutes and analyzed using Image J software. After manually outlining the stomach, the software was used to calculate the area of the image of the stomach. The area directly after gavage of the meal was set at 100% and GE was expressed as the fraction of the original stomach area over time. The average percentage emptied over 60 minutes was compared. Data were represented as mean±S.E.M. and compared using a paired ttest (p 0.1). Atropine caused a significant delay in GE compared to vehicle (55.6±3.1 vs. 40.3±2.7% emptied over 60 minutes, p<0.01). Similarly, PP-treatment significantly inhibited GE (60.5±3.2 vs. 48.5±1.9% emptied over 60 minutes, p<0.05; Fig.1). Conclusion: Using X-rays to visualize a radio-opaque meal allows to determine gastric emptying in a continuous non-invasive manner. Both atropine and PP significantly delayed gastric emptying rate.