Effects of Gadolinium Complexes on Spinal Cord Cell Cultures
In various tissues, gadolinium (Gd 3+) has been shown to modify calcium-influx-related metabolic functions and to block the binding of calcium to the plasma membrane. The question arises as to whether magnetic resonance (MR) contrast media are able to interact with plasma-membrane calcium binding sites or calcium channels. The object of this study was to investigate the possibility of a fixation of gadolinium at the neuronal cell surface, and/or its penetration inside the cell. To distinguish the effect of ionic gadolinium from that of complexed gadolinium and to improve sensitivity, we used radioactive compounds: MR contrast media were labelled with gadolinium 153 (γ) and carbon 14 (β). In all experiments cultured mouse spinal cord cells were used. The techniques of preparing dissociated cell cultures have been previously described by Allard et al [J. Neurochem. 48, 1553–1559 (1987)]. Cells were plated in Falcon plastic tissue culture dishes 3.5 mm diameter at a density of 2 × 106 cells/dish in 1.5 ml of nutrient medium at 37° C. After 8 days, cell cultures were incubated for 3 days in 0.5 ml of nutrient medium containing 0.3 mCi of DTPA  Gd or DOTA  Gd (at a final concentration of 50 nM) or 0.4 mCi of [14C]DTPA Gd or [14C]DOTA Gd (at a final concentration of 50 nM). Then, the supernatant was transferred into vials to quantify radioactivity. Each well was rinsed twice with 200 μl of medium, then the radioactivity of the pellet was measured. The structural integrity of the cells was assessed by morphological criteria and the leakage of cytoplasmic lactate dehydrogenase. The pellet containing spinal cord cells contained 1 to 2% of the initial radioactivity. These results show that neuronal cells and MR contrast media interact.