Saldeña T A, Saraví F D, Hwang H J, Cincunegui L M, Carra G E
Cátedra de Física Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
Dig Dis Sci. 2000 Nov;45(11):2108-14. doi: 10.1023/a:1026411118033.
The contributions of subepithelial tissue, mucosa, and mucus gel layer as restraints for oxygen diffusion in rat distal colon in vitro were assessed by comparing oxygen transfer through preparations of isolated submucosa, isolated mucosa with and without the superficial mucus gel layer, and mucosa-submucosa mounted as flat sheets in a diffusion chamber. One side of the chamber was gassed with 95% O2-5% CO2 while the time course of oxygen concentration rise was measured in the continuously stirred opposite side, initially equilibrated with near-zero oxygen solution. The procedure does not affect epithelial viability. Diffusion in isolated mucosa was the same before and after KCN (5 mM) treatment, suggesting that epithelial oxygen consumption does not influence transfer rates. Subepithelial tissue, mucosa, and mucus gel layer are roughly responsible, respectively, for 12%, 56%, and 32% of oxygen diffusive hindrance. Diffusion coefficients range from 13% (mucosa-submucosa) to 54% (isolated submucosa) of that of water. Subepithelial tissue accounts for about 12% of total diffusive restraint.
通过比较氧气在以下几种制剂中的传输情况，评估了大鼠离体远端结肠中上皮下组织、黏膜和黏液凝胶层作为氧气扩散限制因素的作用：分离的黏膜下层、带有和不带有表面黏液凝胶层的分离黏膜，以及在扩散室中作为平板安装的黏膜 - 黏膜下层。扩散室的一侧用95% O₂ - 5% CO₂ 通气，同时在持续搅拌的另一侧测量氧气浓度升高的时间进程，该侧最初用接近零氧溶液平衡。该程序不影响上皮细胞活力。KCN（5 mM）处理前后，分离黏膜中的扩散情况相同，这表明上皮细胞的氧气消耗不影响传输速率。上皮下组织、黏膜和黏液凝胶层分别约占氧气扩散阻碍的12%、56%和32%。扩散系数为水的扩散系数的13%（黏膜 - 黏膜下层）至54%（分离的黏膜下层）。上皮下组织约占总扩散限制的12%。
