Methylene blue prevents surgery-induced peritoneal adhesions but impairs the early phase of anastomotic wound healing.
OBJECTIVE
Adhesion formation continues to be an important problem in gastrointestinal surgery. In recent years, methylene blue (MB) has been reported to be an effective agent for preventing peritoneal adhesions. However, its effects on the wound healing process are unknown. In the present study, we investigated the effects of MB on the early and late phases of anastomotic wound healing and on adhesion formation.


METHODS
We randomly categorized 92 rats into 2 groups in bursting pressure measurements and 50 rats into 3 groups in the adhesion model. We divided the animals into saline-treated (n = 46) or MB-treated (n = 46) groups. Bursting pressures of the anastomoses were measured on postoperative days 3 and 7. In biochemical studies, tissue hydroxyproline levels, total nitrite/nitrate levels and nitric oxide synthase activity were measured on postoperative days 3 and 7. In the adhesion model, we randomly categorized rats into sham (n = 10), saline-treated (n = 20) and MB-treated (n = 20) groups, and the formation of intraperitoneal adhesions was scored on postoperative day 14. We compared the measurement of bursting pressure and biochemical measurements of tissue hydroxyproline levels, total nitrite/nitrate levels and nitric oxide synthase activity. Histopathological findings of specimens were presented.


RESULTS
During the early phase of wound healing (postoperative day 3), bursting pressures, tissue hydroxyproline, total nitrite/nitrate levels and nitric oxide synthase activity in the MB-treated group were significantly lower than those of the saline-treated group. On postoperative day 7, there was no significant difference in these parameters between MB and saline-treated groups. In the adhesion model, MB caused a significant reduction in the formation of peritoneal adhesions.


CONCLUSIONS
MB prevents peritoneal adhesions but causes a significant impairment of anastomotic bursting pressure during the early phase of the wound healing process by its transient inhibitory effect on the nitric oxide pathway.
Dinc
Soykan
S
Department of General Surgery, Ankara Oncology Training and Research Hospital, Turkey.
Ozaslan
Cihangir
C
Kuru
Bekir
B
Karaca
Sefa
S
Ustun
Huseyin
H
Alagol
Haluk
H
Renda
Nurten
N
Oz
Murat
M
D000818:Animals; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005500:Follow-Up Studies; D007813:Laparotomy / Q000009:adverse effects; D008297:Male; D008751:Methylene Blue / Q000627:therapeutic use*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010532:Peritoneal Diseases / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D010537:Peritoneum / Q000187:drug effects / Q000473:pathology*; D011183:Postoperative Complications; D051381:Rats; D017207:Rats, Sprague-Dawley; D000267:Tissue Adhesions / Q000517:prevention & control; D016896:Treatment Outcome; D014945:Wound Healing / Q000187:drug effects*
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D008751:Methylene Blue