Abstract
Introduction
The diagnostics of discogenic low back pain may employ also radioopaque contrast agents, such as iodixanol, which may cause cytotoxicity to intervertebral disc cells following the intradiscal injections, provoking or accelerating the degeneration process. As many studies so far have been accomplished on animal cells, the potential effects of these agents in humans still remain unclear. The study aim was to evaluate the effect of iodixanol on human intervertebral disc cells in vitro and to compare its cytotoxicity to saline solution control.
Material and Methods
From human lumbar intervertebral disc fragments obtained during discectomis, annulus fibrosus and nucleus pulposus cells were isolated, cultured on the microtiter plates and exposed to various concentrations of iodixanol. Saline was used as a control. Three different dilutions (undiluted, 1:2 and 1:4) of iodixanol were tested. After 6, 24 and 48 hours, viability was determined.
Results
A time and dose depended response to iodixanol exposure was observed. The nulceus pulposus cells were more susceptible than annulus fibrosus cells to its toxic effects. Iodixanol was cytotoxic in all three tested concentrations (undiluted, 1:2 and 1:4) with the cell survival of 0%, 8% and 14%, respectively. Necrosis, rather than apoptosis, was the main reason for such devastating effects.
Conclusion
In iodixanol, commonly used for discography, the cytotoxic effects were observed in a dose- and time-dependent manner. According to our study, concentrated iodixanol is best avoided due to its high toxicity. Although 1:4 dilution was least toxic and may be thus recommended for the intradiscal diagnostics, the high dilutions are questionable due to loss of resolution yield. We assume the toxic effects of the contrast agents used may also contribute to disc degeneration, culminating to progressive tissue damage after the diagnostic measures.