The effect of macrocyclic ionic and non-ionic gadolinium agents on neuronal injury and myelin loss in the spinal cords of rats with and without diabetes mellitus

Background The effect of gadolinium-based contrast agents (GBCA) on the spinal cord is not established, especially in patients with diabetes mellitus. Purpose To investigate neuronal and myelin loss in the spinal cord when employing macrocyclic ionic Gadoterate Meglumine (Gd-DOTA) and non-ionic Gadobuterol (Gd-BT-DO3A) GBCA in rats with and without diabetes mellitus. Materials and methods This study was performed between November 2018 and February 2020. Sixty young Sprague Dawley white rats (n = 6/group) were given injections of two macrocyclic GBCA: 0.5 mmol/ml Gd-DOTA and 1 mmol/ml Gd-BT-DO3A, using volumes based of the recommended doses (0.1 ml and 0.2 ml) for 42 days in both healthy and diabetic rats. Control groups received saline injections. Morphological assessment of spinal cord tissues was performed on three spinal segments. Neuronal counts in the ventral horns and myelin sparing percentage in the white matter were determined and compared in each group employing one-way ANOVA and Dunnett test for each category followed by three-way factorial analysis. Results Low neuronal count and myelin percentage-area were obtained in groups receiving 0.2 ml Gd-DOTA (p = .001;p = .002;p < .001 neurons; and p < .001;p = .007;p = .001 myelin %) and Gd-BT-DO3A (p = .01;p = .048;p = .006 neurons; p < .001;p = .01;p = .001 myelin %). Similarly, neuronal loss was seen in diabetics receiving low volume-injection (0.1 ml) of Gd-DOTA (p = .04;p = .03;p = .42), Gd-BT-DO3A (p = .002;p = .007;p = .01); or high volume-injection (0.2 ml) of Gd-DOTA (p = .001;p = .003;p = .01) or Gd-BT-DO3A (p < .001,p = .002;p = .002), with associated decrease in myelin sparing for each category with low dose Gd-DOTA (p < .001, p = .001; p. = 09),Gd-BT-DO3A (p = .003;p = .003;p = .007); or the higher dose counterparts of Gd-DOTA (p < .001; p < .00; p = .001) and Gd-BT-DO3A (p < .001, p < .001, p < .001).Damage was observed using the standard dose (equivalent of 0.1 mmol/kg for rats) of Gd-DOTA (0.2 ml) but not that of Gd-BT-DO3A (0.1 ml) in healthy rats. Conclusion Multiple high-volume injections of gadoterate meglumine and gadobuterol are associated with neuronal and myelin injury in the spinal cord, more so in rats with diabetes mellitus.