Alterations of Macrophage Migration Inhibitory Factor Expression in the Nervous System of the Rat Cystitis Model

Objective: We evaluated the changes in the migration inhibitory factor (MIF) expression with time in the bladder and spinal cord of a Sprague-Dawley rat cystitis model.

Methods: The bladder created by injecting lipopolysaccharide (LPS) and the lumbosacral spinal cord were removed at 4, 24, and 48 h, and 7 days after the induction of chronic cystitis, and 24 h after the induction of acute cystitis. The MIF expression was estimated using immunohistochemical staining, and the MIF mRNA was quantitatively analyzed using real-time polymerase chain reaction.

Results: The MIF expression in the urothelial cell was lowest at 24 h after LPS injection. As the degree of inflammation decreased, the MIF expression in the urothelial cell gradually increased 48 h and 7 days. The quantitative analysis of the MIF mRNA showed that the MIF expression was highest in both the bladder and the lumbosacral spinal cord 24 h after the cystitis became most severe. In chronic cystitis, the MIF mRNA expressions in the bladder and the lumbosacral spinal cord were 2.8 and 2.1 times significantly higher than in the normal control.

Conclusion: MIF is involved in urinary symptoms and pain in cystitis, and in the mechanism that prolongs the symptoms of chronic cystitis by involving bladder tissue, and the nervous system.