Comparative rheological profile of rat gastric and duodenal gel mucus

Methods for measuring the adhesiveness, plasticity, viscoelasticity and spinnability of mucus microsamples have been developed. The rheological properties of the rat gastric and duodenal gel mucus have been analyzed and compared. Using a controlled stress rheometer (Carri-Med), flow and creep experiments showed that gastroduodenal mucus exhibits a typically non-newtonian, pseudoplastic and viscoelastic behaviour. The apparent viscosity (7,800 +/- 11,000 Pa.s) and yield stress (24.9 +/- 8.5 Pa) of gastric mucus were significantly higher than the duodenal mucus viscosity (39 +/- 160 Pa.s) and yield stress (12.9 +/- 2 Pa). Spinnability of gastric mucus, measured with a Filancemeter (SEFAM), was significantly lower (4.9 +/- 2.5 mm) in comparison to duodenal mucus (6.9 +/- 1.5 mm). Adhesive properties of gastric mucosa (analyzed with the platinum ring method) were not significantly different in comparison to duodenal mucus (99.9 +/- 31.5 mN/m and 92.8 +/- 11.2 mN/m, respectively).