**2.2 Hyaluronic acid**

Hyaluronic acid (HA) is a component of the glycosaminoglycan (GAG) layer of the bladder and is used to repair the GAG layer. A previous study synthesis in an inflammatory model of IC/BPS indicated that the mechanism of action involves modulation of urothelial permeability and stimulation of GAG [10]. HA is used at a concentration of 0.8% for intravesical instillation treatment for IC/BPS. In a previous study in which intravesical HA was administered for 4 weeks with monthly instillation for 6 months in patients with refractory IC/BPS, the response rate at 12 weeks was 71% and was maintained well until 20 weeks. In a study comparing HA and heparin intravesical instillation after hydrodistension, the therapeutic effect of severe IC/BPS patients was maintained longer in patients who received HA instillation than those who received heparin.
