As many organs, including the kidneys, are partially controlled by sympathetic innervations, some have suggested that the level of spinal cord injury (SCI) should play a role in alterations of renal function. This study explored the relationship between SCI level and renal function.

Three groups of rats were studied, including sham-injured rats, rats injured at the T-1 level and rats injured at the T-8 level. All animals demonstrated complete paraplegia at 24 hours post-injury. Tubular secretion (TS) and glomerular filtration rate (GFR) were calculated by measuring the pharmacokinetics of iopamidol, a radiopaque contrast excreted by the kidneys, and P-aminohippuric acid (PAH), with a known renal extraction ratio.

Both groups of injured rats demonstrated decreased GFR and TS. However, only the T-1 injured group showed statistically significant differences in pharmacokinetics, as compared with the sham-injured group. In the T1-injured group, iopamidol clearance was decreased by 90% (P<0.5) and iopamidol AUC and half-life were increased by 10.7 and 6.5-fold, respectively (P<0.01). In the T-8 injured group, the iopamidol clearance dropped by 67% (P<0.01) and the AUC and half-life increased by three- and 1.5-fold, respectively (P<0.01). PAH clearance was reduced in the T1 group by 75% (P<0.01), and in the T8 group by 41% (P<0.01)．

This animal study found that the level of spinal cord injury may be a prognostic factor for the severity of loss of kidney function following that injury.