Prevent Post-Operative Intestinal Adhesion By Using Biodegradable Thermoreversible Pcla-Peg-Pcla Hydrogel In Rabbits

Biodegradable thermoreversible hydrogel used to prevent post-operative intestinal adhesion in rabbitsOBJECTIVES:With the biodegradable thermoreversible triblock (PCLA-PEG-PCLA) hydrogel, we investigate how to prevent post-operative intestinal adhesion in rabbits.what's more, we treated rabbits with the PCLA-PEG-PCLA hydrogel encapsulating RGD to improve Post-operative adhesion preventionMATERIALS and METHODSPart 1, Biodegradable thermoreversible PCLA-PEG-PCLA hydrogel used to prevent post-operative intestinal adhesion in rabbits:The anti-adhesion efficacy of the hydrogel was tested using a rabbit model of sidewall defect-bowel abrasion, White New Zealand rabbits (2.5±0.2 kg) were used as model animals and randomly divided into 3 groups. For the animal of "Gel" group (n=7),4 mL of the PCLA-PEG-PCLA solution was injected to cover the defects, and gelation happened rapidly in situ, For the group of "Film" (n=7), the defect was covered by a 5 X 5 cm2 sterilized PLA film (DIKFILM(?), DiKang) without suturing. Six animals with their defects untreated were set as control.30 days after surgery, rabbits were euthanized to examine post-operative adhesion, and the tissue regeneration on defect was checked at the same time. Planimetry was used to determine area of the sidewall injury where intestinal adhesion had developed. Specimens were fixed in 10% formalin, embedded in paraffin, sectioned and stained with HE staining for histological examination.Part 2, Biodegradable thermoreversible PCLA-PEG-PCLA hydrogel encapsulating RGD used to prevent post-operative intestinal adhesion in rabbits:a rabbit model of sidewall defect-bowel abrasion was the same as the part 1. White New Zealand rabbits (2.5±0.2 kg) were used as model animals and randomly divided into 4 groups. For the animal of "Gel+RGD" group (n=6),4mL of the PCLA-PEG-PCLA encapsulating RGD solution was injected to cover the defects, and gelation happened rapidly in situ, For the group of "Gel" (n=6), the defect was covered by PCLA-PEG-PCLA hydrogel. For the group of "RGD" (n=6),the defect was covered by RGD solution, and six animals with their defects untreated were set as control.7days after surgery, rabbits were euthanized to examine post-operative adhesion, and the tissue regeneration on defect was checked at the same time. Planimetry was used to determine area of the sidewall injury where intestinal adhesion had developed. Specimens were fixed in 10% formalin, embedded in paraffin, sectioned and stained with HE staining for histological examination.RESULTSPart 1:after 30 days, a significant reduction of post-operative peritoneal adhesion has been found in the group of in situ formed PCLA-PEG-PCLA hydrogels.Part 2:after 7 days, we found the rabbits treated by Gel+RGD showed a more significant reduction of post-operative peritoneal adhesion than those treated by Gel.Conclusions:The Biodegradable thermoreversible PCLA-PEG-PCLA hydrogel and The Biodegradable thermoreversible PCLA-PEG-PCLA hydrogel encapsulating RGD have a significant reduction of post-operative peritoneal adhesion.