SURFACE HYDROPHOBICITY PROPERTIES OF RABBIT STOMACH IN-VITRO

To quantitate surface hydrophobicity of the stomach, we measured conta ct angles formed with water droplets in different regions of rabbit st omach at varying ages (suckling, weanling, and adult). Contact angles were measured using novel methods: axisymmetric drop-shape analysis-co ntact diameter for contact angles < 90 degrees and axisymmetric drop-s hape analysis-maximum diameter for contact angles > 90 degrees. To det ermine whether gastric mucus was responsible for the physical properti es of the surface mucosa, the surface tension of mucus derived from th e body of stomach was measured by axisymmetric drop-shape analysis on pendant drops. Contact angles of adult antrum 82.9 degrees +/- 5.5 deg rees (mean +/- SEM) were greater than in the body of stomach (36.1 deg rees +/- 2.6 degrees, p = 0.0001). Contact angles on mucosa obtained f rom the body of the stomach of both suckling rabbits (76.4 degrees +/- 2.7 degrees) and weanling rabbits (84.2 degrees +/- 2.9 degrees) were greater than in adult animals (ANOVA, p < 0.05). Pendant drop analysi s of mucus derived from the body of stomach showed a high surface tens ion (57.72 +/- 0.06 mJ/m(2), mean +/- SD). We conclude that there are maturational changes and regional differences in the surface hydrophob icity of the lapine stomach. These changes are likely caused by change s in the overlying mucus layer.