Preventive Effects of Hyaluronic Acid on Escherichia coli-induced Urinary Tract Infection in Rat

ObjectivesTo investigate the effects of hyaluronic acid (HA) in rat with Escherichia coli-induced urinary tract infection and duration of its effect. HA is a component of the glycosaminoglycan layer, and is known to interfere with the attachment of E. coli to the urothelium.MethodsThe rats were divided into various groups. The E. coli-only group in which phosphate-buffered saline was instilled before E. coli (fimH+, sfa+, papA+) inoculation; HA-1, HA-3, HA-5, and HA-7 groups in which HA (0.5 mL, 0.5%) was instilled 1, 3, 5, 7 days before E. coli inoculation, respectively. To assess the symptomatic changes, we examined the voiding interval (VI) of E. coli-only group and HA-1 group before and after E. coli inoculation. Atomic force microscopy was performed to investigate the change in the urothelium before and after HA treatment.ResultsBacterial growth rate in the bladder was significantly higher in the E. coli-only group (84.6%) than in the HA-1 (20.0%), HA-3 (23.5%), and HA-5 groups (7.7%) (P <.05). The VI in E. coli-only group decreased from the first to third day after the induction of cystitis. The VI in E. coli-only group was significantly shorter than in HA-1 group (P <.05). No pathological evidence of acute inflammation was observed in the bladder and kidney of culture-negative HA groups. Atomic force microscopy showed HA coating on the urothelium.ConclusionsThis study shows that HA has an effect on the protection mechanism against the invasion of E. coli and that its effect duration is about seven days.