Mucosal protection during irradiation of exteriorized rat ileum. Effect of hypoxia induced by starch microspheres.

Transient hypoxia induced by intra-arterial injection of degradable starch microspheres was used for protection of exteriorized segments of the rat ileum. Microscopic evaluation of the injury to the mucosa gave a dose modification factor of 0.44 +/- 0.04, which corresponds to an oxygen enhancement ratio of 2.30. A similar factor was also found from measurements of the mucosal weight. No significant development of mucosal oedema could be demonstrated, neither in protected nor in non-protected segments.