902 MACROPHAGE MIGRATION INHIBITORY FACTOR (MIF) MRNA EXPRESSION IN THE BLADDER AND LUMBOSACRAL SPINAL CORD LPS-INDUCED CYSTITIS

Abstract

INTRODUCTION AND OBJECTIVES: Macrophage migration inhibitory factor (MIF) is an important pro-inflammatory cytokine expressed at sites of inflammation. This study examined alteration of MIF expression in the bladder and lumbosacral spinal cord of LPS-induced cystitis model according to time. METHODS: Female Sprague-Dawley rats were anesthetized and a angiocatheter was introduced transurethrally into the bladder. Acute cystitis was induced by infusing LPS into the bladder and chronic cystitis was induced by LPS instillations performed every 24 hours for 4 days. In time course studies, rats were euthanized at 4 hours, 24 hours, 48 hours and 7 days after LPS treatment. Chronic cystitis rats were sacrificed 24 hours after the last instillation. The bladder and lumbosacral spinal cord (L6/S1) were then removed and assayed for MIF expression. The expression of MIF was investigated by real-time PCR. RESULTS: The MIF mRNA was up-regulated in the bladder and lumbosacral spinal cord, peaking 24 hours after LPS treatment shown by real-time PCR. Following chronic cystitis, significant MIF mRNA increased were observed in bladder and lumbosacral spinal cord (bladder: 2.8-fold, L6/S1: 2.1-fold) (p 0.05). CONCLUSIONS: LPS-induced cystitis in rats increases the MIF mRNA expression in the bladder and lumbosacral spinal cord. MIF up-regulation may represent a neural response to visceral inflammation. MIF may contribute to the development or maintenance of hyperalgesia and/or urinary bladder hyperreflexia and suggest MIF may be a potential target of inflammatory pain. Source of Funding: Astellas company