Immunostimulating and Prophylactic Effect of Escherichia coli Extract in a Mouse Model of Lipopolysaccharide-induced Cystitis

Lee, Seung Ju; Lee, Choong Hyun; Kim, Sae Woong; Cho, Yong Hyun; Yoon, Moon Soo

Abstract

PURPOSE: A bacterial extract consisting of immunostimulating components derived from 18 Escherichia coli strains has been used for the prophylaxis of recurrent cystitis. To evaluate the prophylactic effect of the E. coli extract, the cytokine levels of bladder tissue were measured after oral administration, and the bladder inflammation analyzed by histopathologic examination in a mouse model of lipopolysaccharide(LPS)-induced cystitis.
MATERIALS AND METHODS
After 10-days of E. coli extract administration, the cytokine [interleukin-6(IL-6), IL-10, monocyte chemoattractant protein-1(MCP-1), interferon-gammaIFN-gamma, Tumor necrosis factor-alphaTNF-alpha, IL- 12p70] levels in the bladder of female Blab/C mice were determined using a cytometric bead array. The bladder macrophage inflammatory protein-2 (MIP-2) level was also measured using a sandwich enzyme immunoassay. After immunization with the E. coli extract, E. coli LPS was instilled into the bladders. Twenty-four hours later, the mice were sacrificed and the inflammation of the bladder quantified using the bladder inflammatory index (BII).
RESULTS
Significant increases of the IL-6 and IFN-gammalevels in bladder tissue were observed after E. coli extract treatment. Secretions of the other cytokines were not stimulated by the E. coli extract. Bladders instilled with LPS showed high inflammation scores for edema, leukocyte infiltration, and hemorrhage in the saline treated control mice. In contrast, the E. coli extract treated mice exhibited mild inflammation of their bladders, with significant reduction in their BII scores compared to controls.
CONCLUSIONS
These results demonstrate that immunization using oral treatment of E. coli extract provides protection against the inflammatory responses in a mouse model of LPS-induced cystitis.