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

Bing Yang^1,2*, ChangYang Gong^1*, Xia Zhao², ShengTao Zhou², ZhengYu Li², XiaoRong Qi², Qian Zhong², Feng Luo¹, ZhiYong Qian^1
1State Key Laboratory of Biotherapy, West China University Hospital, Sichuan University, Chengdu, People's Republic of China; ²Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, Chengdu, People's Republic of China
^*These authors contributed equally in this work

Background: Poly (ethylene glycol)-poly (ε-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