Objectives: This study is carried out to explore clinical and histological changes induced in rats by intrathecal administration of Gd-DTPA via suboccipital spinal injection. 2.5, 5, 10 μmol/g-brain of Gd-DTPA were injected intrathecally to 43 adult male rats and sucrose as control solution with same volume and osmolarity were injected to 18 rats. Animals were sacrificed on day 4 and 14. Sections from the cortex, brain stem, cerebellum and medulla spinalis were obtained to examine for cell loss and apoptosis. In this study, no clinical abnormalities were observed in 69.8 % of rats of Gd-DTPA group and in 83.3 % of rats of sucrose group. Transient neurological signs such as ataxia and paresis were seen in 11.6 % of rats in the Gd-DTPA group and in 5.5 % of rats in the sucrose group. They were seen more frequently in the Gd-DTPA group especially in the highest dose and volume. Histological examination did not revealed necrosis or apoptosis in both groups. This study suggests that intrathecally administered Gd-DTPA may be safe in humans when lower doses per gram of brain are used than rats.
