Hypoxia mediated binding of misonidazole in non-malignant tissue.

Binding of 3H-misonidazole in hypoxic nonmalignant tissue was investigated in the gerbil stroke model. Cerebral infarcts were produced in male Mongolian gerbils by ligating the right common carotid artery and the severity of the lesions was quantified by scoring the animals' symptoms. The uptake of [H-3]misonidazole in the right cerebral hemisphere and the ratios of right:left hemispheral uptake correlated positively with the severity of the stroke when measured 6 to 10 hours after carotid ligation. Autoradiographs of the gerbil brains with severe infarcts showed heavy label, which was uniformly distributed, on the affected side. We conclude that the gerbil stroke model is useful for studying hypoxia in vivo. There is variability between animals that closely correlates with stroke index, but more importantly the hypoxia may be more homogeneous over regions of the brain within one animal. A reliable model of homogeneous induced hypoxia in vivo will be useful for evaluating radiolabeled drugs which may be used for quantitation of hypoxia in tumors by nuclear imaging.