Hypothermia Increases Tissue Plasminogen Activator Expression and Decreases Post-Operative Intra-Abdominal Adhesion

BACKGROUND: Therapeutic hypothermia during operation decreases postoperative intra-abdominal adhesion formation. We sought to determine the most appropriate duration of hypothermia, and whether hypothermia affects the expression of tissue plasminogen activator (tPA). METHODS: 80 male BALB/c mice weighing 25–30 g are randomized into one of five groups: adhesion model with infusion of 15°C saline for 15 minutes (A); 30 minutes (B); 45 minute (C); adhesion model without infusion of cold saline (D); and sham operation without infusion of cold saline (E). Adhesion scores and tPA levels in the peritoneum fluid levels were analyzed on postoperative days 1, 7, and 14. RESULTS: On day 14, the cold saline infusion groups (A, B, and C) had lower adhesion scores than the without infusion of cold saline group (D). However, only group B (cold saline infusion for 30 minutes) had a significantly lower adhesion scores than group D. Also, group B was found to have 3.4 fold, 2.3 fold, and 2.2 fold higher levels of tPA than group D on days 1, 7, and 14 respectively. CONCLUSIONS: Our results suggest that cold saline infusion for 30 minutes was the optimum duration to decrease postoperative intra-abdominal adhesion formation. The decrease in the adhesion formations could be partly due to an increase in the level of tPA.