Basic study of healing of injuries to the myometrium and amniotic membrane using photocrosslinkable chitosan

We performed in vivo and in vitro adhesion experiments on the use of photocrosslinkable chitosan (PC) for healing of the myometrium and the amniotic membrane to test its usefulness in the perinatal field.

To determine the adhesion conditions of PC in the healing of the myometrium and amniotic membrane, we applied two concentrations (30 and 50 mg/mL) of PC to the postpartum amniotic membrane, and radiated it with ultraviolet (UV) light for 10, 20, 30 or 60 s. Next, we created incisions of three sizes (pinhole, 5 mm and 10 mm), and performed PC adhesion followed by pressure application experiments. Subsequently, we laparotomized 12-day-pregnant rats under anesthesia, created a 5-mm incision, applied PC and closed the abdomen. We removed the uterus at 20 days of pregnancy, and histologically examined the site of PC application.

The optimal adhesion conditions of PC were 50 mg/mL, and the optimal time of UV irradiation was 30 s or longer. In pressure application experiments, the bonding strength of PC was so high that even 10-mm incisions withstood a mean pressure of 92 mmH2O. The bonding strength of PC was significantly higher than that of fibrin glue that was tested in parallel. Histological examination of the rat myometrium showed a mild foreign body reaction with no inflammatory findings, confirming the usefulness of PC.

PC is a wound-healing drug, an improvement on the naturally occurring polysaccharide chitosan, and is safer and has a higher bonding strength than biological adhesives including fibrin, making it promising for fetal surgical and perinatal applications.