The Expression of Proinflammatory Cytokine and Macrophage Migration Inhibitory Factor in a Rat Lipopolysaccharide-Induced Cystitis Model / 대한비뇨기과학회지

ABSTRACT

PURPOSE: We wanted to evaluate the changes of the expression of macrophage migration inhibitory factor(MIF) according to time, so we determined the semiquantitative score from immunostaining in a bladder inflammatory rat model. MATERIALS AND METHODS: A total of 25 female Sprague-Dawley rats were divided into 5 groups according to the time course. Group 1 was the control group that was treated with an intravesical instillation of saline. Groups 2-5 were evaluated at 4 hours, 24 hours, 48 hours and 7 days after the instillation of lipopolysaccharide(LPS), respectively. H&E staining and immunohistochemical staining for MIF were performed after removing the bladder. A semiquantitative score was used to evaluate the cystitis(bladder inflammation score; BIS). The expression of MIF in the bladder was graded from 0 to 3+(MIF score; MIFS). RESULTS: The staining of MIF was the most intense in the basal layer of the urothelium in the control group(BIS 0, MIFS 3). The degree of bladder inflammation was highest in group 3, and MIF was not expressed even in the urotherlium without inflammation(BIS 2.2, MIFS 0.6). The bladder inflammation was decreased after 48 hours, and the expression of MIF was increased after 48 hous(BIS 1.7, MIFS 1.6). The severity of bladder inflammation and the expression of MIS were significantly changed with the time course(p<0.001). CONCLUSIONS: These results suggest that pre-formed MIF is stored in the cytoplasm of the basal cells in the urothelium, and it is released into the lumen of the bladder after a noxious stimulus like LPS.