Hk. Galtung et al., Effect of radiologic contrast media on cell volume regulation in rabbit proximal renal tubules, ACAD RADIOL, 8(5), 2001, pp. 398-404
Rationale and Objectives, Most radiographic contrast media are hyperosmotic
and able to shrink cells with which they are in contact. The authors studi
ed cell volume control in rabbit proximal renal tubules after incubation wi
th three contrast media: iohexol, ioxaglate, and iodixanol.
Materials and Methods. Proximal renal tubales were isolated from rabbit kid
neys. The tubules were exposed to Ringer solutions containing 5% vol/vol io
hexol (final osmolality, 330 mOsm), ioxaglate (323 mOsm), iodixanol (305 mO
sm), or mannitol (control solutions with identical osmolalities), and tubul
e volumes were monitored. After 2 hours of incubation, the tubules were sti
mulated with a hyposmotic Ringer solution (165 mOsm). Three groups of 10 ex
periments were performed.
Results. All solutions induced cell shrinkage (8.3% +/- 3.8 [standard error
] to 15.4% +/- 0.5), which was completely or partly reversible in most expe
riments (volume increase, 44.8% +/- 14.7 to 149.9% +/- 107.3) but not those
with iohexol and iodixanol, With exposure to the hyposmotic solution, the
cells swelled by 11.0% +/- 1.8 to 39.7% +/- 4.8. In general, the tubules th
at had been exposed to the most hyperosmotic solution swelled the most. Tho
se exposed to contrast media showed less swelling than the mannitol-exposed
controls. In all control experiments, the cells exhibited a gradual shrink
age (43.6% +/- 28.5 to 87.0% +/- 13). This regulatory response was partly
inhibited in tubules exposed to iohexol (39.9% +/- 15.8 shrinkage) or iodix
anol (8.9% +/- 15.8) and completely inhibited in those exposed to ioxaglate
. Iohexol and ioxaglate exposure also led to a decrease in water permeabili
ty.
Conclusion. Exposure to hyperosmotic contrast medium tends to induce prolon
ged cell shrinkage, decrease the water per meability of the cellular plasma
membranes, and compromise the ability to regulate cellular volume. These c
hanges seem to reflect both the hyperosmolality of the solutions and their
inherent chemical properties.