Preventive effects of hyaluronic acid on Escherichia coli-induced urinary tract infection in rat

Objectives: To 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.

Methods: The 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.

Results: Bacterial 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.

Conclusions: This 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.