APOPTOSIS IS RESTRICTED TO THE THALAMUS IN THIAMINE-DEFICIENT RATS

THIAMINE deficiency (TD) produces lesions in the thalamus, mamillary a nd medial geniculate nuclei, and inferior colliculus. To clarify the p athogenesis of these lesions, we examined the occurrence of hallmarks of apoptosis following TD in rat brain. Histological assessment showed apoptotic cells in the thalamus and medial geniculate nucleus but not in the inferior colliculus. We used terminal deoxynucleotidyl transfe rase-mediated deoxyuridine (dUPT)-biotin nick-end labelling (TUNEL) an d gel electrophoresis to demonstrate that TD is associated with apopto tic cell death. In the thalamus, DNA fragmentation appeared from day 1 4 of deficiency and preceded the appearance of ataxia. The inferior co lliculus and mamillary nucleus were without electrophoretic DNA fragme nts, and only rare TUNEL-positive labelling was observed. This model s hows a rare combination of both apoptosis and necrosis in the same les ioned brain.