In vivo MR assessment of hippocampal volume and neurochemical changes in rats with altered corticosteroid milieu

Hippocampal pathology seems to be a hallmark of various mental diseases. Over the last decade, high-resolution MRI enabled ready assessment of such volume changes in extensive patient databases. These studies together with histological evidence of glucocorticoid-induced neurotoxicity in rats have led to the hypothesis that hippocampal volume loss in major depression may result from elevated levels of glucocorticoids (1-6), but direct evidence is lacking. To further characterize the nature of these hippocampal volume changes, this combined ultrahigh-field MRI and MRS study was performed in rats with long-term alterations of the corticosteroid milieu. Animals were pretreated in analogy to previous histological studies (7, 8) to (i) analyze whether