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Effect of chymopapain on the meninges studied in an experimental model
V M Haughton1, C M Nguyen, K C Ho
1Department of Radiology, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, Milwaukee 53226.
Abstract:
The effect of chymopapain and contrast media in the epidural space on meninges has not been studied conclusively. The authors injected chymopapain into the epidural space of monkeys and measured the degree of arachnoid fibrosis that resulted. Animals were given injections of 1.2 mL of diatrizoate (280 mg iodine per milliliter), chymopapain (100 IU/mL), kaolin (100 mg/mL) (as a positive control), or saline (0.9%) (as a negative control). Three months later the animals were killed; the dural sac was removed intact and was fixed, sectioned, stained, and examined with light microscopy. Kaolin-treated animals developed mild to marked fibrosis of the dura. The saline- and diatrizoate-treated animals developed little or no evidence of fibrosis. One of four chymopapain-treated animals developed degenerative changes in dorsal nerve roots and fibrosis in the adjacent arachnoid. The other chymopapain-treated animals had little or no evidence of fibrosis. The studies suggest that neither diatrizoate nor chymopapain causes arachnoid fibrosis.
Insights
This study investigated chymopapain and contrast media effects on meninges. Results suggest neither diatrizoate nor chymopapain causes significant arachnoid fibrosis in animal models.
Area of Science:
- Neurosurgery
- Pathology
- Radiology
Background:
- The impact of epidural injections on meningeal tissues remains incompletely understood.
- Chymopapain and contrast media are utilized in spinal procedures, necessitating safety evaluations.
Purpose of the Study:
- To evaluate the potential of chymopapain and diatrizoate contrast media to induce arachnoid fibrosis when administered into the epidural space.
- To assess the histological changes in meninges following epidural injections in a primate model.
Main Methods:
- Monkeys received epidural injections of diatrizoate, chymopapain, kaolin (positive control), or saline (negative control).
- Meninges were harvested three months post-injection for light microscopy analysis of fibrosis and degenerative changes.
Main Results:
- Kaolin induced mild to marked dural fibrosis.
- Saline and diatrizoate groups showed minimal to no fibrosis.
- One chymopapain-treated animal exhibited nerve root degeneration and adjacent arachnoid fibrosis; others showed minimal effects.
Conclusions:
- Epidural administration of diatrizoate contrast media does not appear to cause significant arachnoid fibrosis.
- Chymopapain demonstrated minimal potential for causing arachnoid fibrosis in this study, with one instance of localized changes.