Evaluation of the time-stability of an alternative research model based on isolated rat gastrointestinal strips

Experiments were performed on rat isolated gastrointestinal (GI) strips. The study was carried out in isotonic conditions during a long-term (5-8 h) incubation in modified Krebs-Henseleit solution, (M K-HS) at 37 degrees C. The reaction of GI muscle strips to acetylcholine (ACh) and histological images of the tissues strips were studied. Additionally, spontaneous motor activity of the jejunum strips was evaluated. The obtained results indicate that as well the spontaneous motility as the response of jejunum muscle strips to acetylcholine and the histological structure of the preparations changed throughout the incubation time. It suggests low time-stability of jejunum strips model during long-term experiment. In contrast, the response of stomach (corpus and fundus) strips to ACh application did not change significantly during 6 h incubation. Moreover, the histological structure of the stomach preparations was maintained unaffected for a long incubation time. Thus, the isolated stomach strips can be described as an alternative experimental model of high time-stability during long-term experiments.