Reduction of intercellular adhesion molecule 1 may play a role in anti-inflammatory effect of hyaluronic acid in a rat model of severe non-bacterial cystitis.

PURPOSE: To evaluate the impact of intercellular adhesion molecule 1 (ICAM-1) in hyaluronic acid (HA) therapy in rats model of severe non-bacterial cystitis. METHODS: Cystitis models in Sprague-Dawley female rats were produced by combination of intraperitoneal cyclophosphamide (CYP) with intravesical protamine/lipopolysaccharide (PS/LPS). HA or heparin (0.5 ml) was introduced intravesically to rats' bladders followed PS/LPS. Bladder tissue was prepared for histology including mast cell presence and measurement of ICAM-1, tumor necrosis factor (TNF)-α, and interleukin 6 (IL-6). RESULTS: Cystitis model using intraperitoneal CYP and intravesical SP/LPS showed serious inflammation, higher mast cell count with elevated ICAM-1, TNF-α, and IL-6 levels. After intravesical heparin or HA treatment, incidence of grades 3-4 bladder inflammation and tissue ICAM-1 level were only significantly lower in HA group (P = 0.017, P = 0.021, respectively), but not in heparin group (P = 0.12, P = 0.798, respectively). Remarkably lower level of TNF-α (P = 0.003) and ICAM-1 (P = 0.006) was detected in HA-treated rats compared with heparin-treated rats. Inflammation grade and ICAM-1 level had strong correlation (P < 0.001). IL-6 level after HA or heparin instillation had no difference. CONCLUSIONS: Intravesical administration of HA decreased the severity of bladder inflammation, mast cell presence, and levels of ICAM-1 and TNF-α in a rat model of severe non-bacterial cystitis; its effect was more obvious than that of heparin. Reduction of ICAM-1 may play a role in the anti-inflammatory effect of HA.