Introduction Intra-abdominal adhesion formation is the main cause of intestinal obstruction and chronic abdominal pain. Although several anti-adhesive agents have been applied to reduce the burden of adhesion-related symptoms, their operability is a major drawback. Nanosheets with PLA which comprise of thin membrane has a great operability and adheres well to the surface of intra-abdominal organs. Therefore, nanosheets with PLA therefore, is considered one of the novel promising anti-adhesive agents. The aim of this study is to evaluate the impact of Nanosheets with PLA on the prevention of intra-abdominal adhesion formation.

Method For the induction of intra-abdominal adhesion, peritoneal defects were created on each side of abdominal wall of C57/BL mice (9 to 10 weeks old) and were covered by anti-adhesive agents (Nanosheets with PLA vs. sodium hyaluronate/carboxymethylcellulose vs. none). The incidence and severity of adhesion were compared within three groups using chi-square test. The infiltration of inflammatory cells was assessed by immunohistochemistry.

Results Mean adhesion scores of nanosheets with PLA, sodium hyaluronate/carboxymethylcellulose or none were 1.0 ± 0.00, 1.4 ± 0.56 and 4.2 ± 0.51, respectively. A significant difference was observed in two comparisons between none and anti-adhesive agents whilst there was no significant difference between anti-adhesive agents. These findings revealed that both anti-adhesive agents could significantly reduce postoperative adhesion formation and the protective effects were comparable between two agents. The infiltration of inflammatory cells (macrophages and T cells) around peritoneal defect was reduced in Nanosheets with PLA, compared with sodium hyaluronate/carboxymethylcellulose.

Conclusion The anti-adhesive effect of nanosheets with PLA was comparable with conventional anti-adhesive agents, such as sodium hyaluronate/carboxymethylcellulose. These protective effects were expectedly obtained through the prevention of direct adhesion to adjacent tissues and the reduced local inflammation.

Disclosure of interest N. Yabe Grant/Research Support from: Toray Industries, Inc., K. Okabayashi Grant/Research Support from: Toray Industries, Inc., M. Tsuruta Grant/Research Support from: Toray Industries, Inc., S. Murai: None Declared, H. Hasegawa Grant/Research Support from: Toray Industries, Inc., Y. Kitagawa Grant/Research Support from: Toray Industries, Inc.