Macroscopic and pathological assessment of methylene blue and normal saline on postoperative adhesion formation in a rat cecum model

Abstract

Background: Adhesion formation after abdominal surgery is a major cause of postoperative bowel obstruction, infertility, and chronic abdominal pain. In this study, we evaluated the effect of normal saline and methylene blue (MB) on postoperative adhesion formation in a rat cecum model.

Methods: A total of 30 Wistar female rats in 2 treatment and 1 control groups underwent midline laparotomy and standardized abrasion of the visceral peritoneum. Normal saline and methylene blue were administrated intraperitoneally at the end of the surgical procedure in 2 treatment groups. Fourteen days after surgery, a re-laparotomy was performed for macroscopic and pathological assessment.

Results: The adhesion grade and extent of the normal saline group was lower than control and MB groups in macroscopic assessment (P<0.05 for both). A comparison of adhesion stages in pathological assessment showed increment in abdominal adhesion by usage methylene blue 1% and demonstrated significant difference between MB and 2 other groups (P<0.05).

Conclusions: Administrated normal saline individually reduce the adhesion grade near cecum. Conversely, usage of methylene blue 1% may unpredictably increase risk of adhesion formation.