Prevention of desiccation induced postsurgical adhesion by thermosensitive micelles

Tissue desiccation is a common cause of postsurgical peritoneal adhesion, which leads a variety of adverse consequences in clinic. Until now, many approaches have been advocated to prevent postsurgical adhesions, but the therapeutic effects were not very encouraging. In this work, biodegradable and thermosensitive poly(ɛ-caprolactone)-poly(ethylene glycol)-poly(ɛ-caprolactone) (PCL-PEG-PCL) micelles were prepared and assigned for anti-adhesion studies. The micelles were a free flowing sol at low temperature, but instantly inverted into a non-flowing gel at physiological temperature, which could serve as a potential candidate as anti-adhesion barrier. A novel cecum desiccation rat model was established and used for anti-adhesion studies. The micelles were sol state before use, which could cover the injured cecum unrestrictedly, and then formed gel in body temperature and adhered to the injured sites. All the rats in the control group developed adhesions with score 5 or 4, whereas none in the micelle-treated group developed adhesions with score 5 or 4 (P<0.001, Mann-Whitney U test). Histopathological assessment also confirmed that the micelles exhibited excellent anti-adhesion effects on desiccation-induced peritoneal adhesion. Adhesiveness and degradation behavior of the micelles suggested that the micelles could adhere to the injured cecum and prevent adhesion in the critical time of healing process. The results indicated that the thermosensitive micelles could serve as an effective anti-adhesion barrier.