Preventing postoperative abdominal adhesions in a rat model with PEG-PCL-PEG hydrogel

Abstract

Background

Poly (ethylene glycol)-poly (ɛ-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG, PECE) hydrogel has been demonstrated to be biocompatible and thermosensitive. In this study, its potential efficacy and mechanisms of preventing postsurgical abdominal adhesions were investigated.

Results

PECE hydrogel was transformed into gel state from sol state in less than 20 seconds at 37°C. None of the animals treated with the hydrogel (n = 15) developed adhesions. In contrast, all untreated animals (n = 15) had adhesions that could only be separated by sharp dissection (P < 0.001). The hydrogel adhered to the peritoneal wounds, gradually disappeared from the wounds within 7 days, and transformed into viscous fluid, being completely absorbed within 12 days. The parietal and visceral peritoneum were remesothelialized in about 5 and 9 days, respectively. The hydrogel prevented the formation of fibrinous adhesion and the invasion of fibroblasts. Also, along with the hydrogel degradation, a temporary inflammatory cell barrier was formed which could effectively delay the invasion of fibroblasts during the critical period of mesothelial regeneration.

Conclusion

The results suggested that PECE hydrogel could effectively prevent postsurgical intra-abdominal adhesions, which possibly result from the prevention of the fibrinous adhesion formation and the fibroblast invasion, the promotion of the remesothelialization, and the hydroflotation effect.

Keywords:

• anti-adhesion
• thermosensitive
• barrier
• biocompatible

Acknowledgments

This investigation was financially supported by National 863 Project (2007AA021804 and 2007AA021902), National Natural Science Foundation (NSFC20704027 and NSFC81071864), Specialized Research Fund for the Doctoral Program of Higher Education (200806100065), Sichuan Key Technology R&D Program (2011SZ0219), and Chinese Key Basic Research Program (2010CB529906).

Disclosure

The authors declare that they have no competing interests.

Authors’ contributions

ZYQ, XZ, FL, BY and CYG designed the experiments. The research funding was supported by ZYQ and XZ. BY, CYG and XRQ carried out the experiments, analyzed the data, and wrote the manuscript; ZYQ, XZ, ZYL, STZ and QZ corrected the manuscript. XRQ and STZ participated in the animal test of the hydrogels. All authors approved and read the final manuscript.