Objective: Cardiopulmonary bypass has been recognized as one of the main causes of systemic inflammatory response syndrome, leading to post-operative complications. The aim of this study was to investigate the effect of melatonin on the serum levels of interleukin 6 (IL-6) and IL-9 in patients undergoing coronary artery bypass grafting surgery.
Methods: Forty-four patients undergoing elective coronary artery bypass surgery were randomly allocated into two study groups of melatonin (n = 23) and placebo (n = 21). Patients in the melatonin group received two melatonin tablet, 5 mg daily for 3 days before surgery, 10 mg tablet (two doses of 5 mg) 1 h before induction of anesthesia and finally, 10 mg melatonin tablet in the intensive care unit, placebo group patients received placebo at the same time periods. Serum levels of IL-9 and IL-6 were measured as baseline (T1), before induction of anesthesia (T2), 6 and 24 h after off pump (T3, T4). Data were analyzed using SPSS 23 software (IBM Corp., Armonk, NY, USA).
Results: The mean serum level of IL-6 was significantly lower in the melatonin group at T3 and T4 (p ＜ 0.05). Also, in both groups, serum levels of IL-6 in T3 showed a significant increase compared to T1. Serum levels of IL-9 had no significant difference between the two groups at T1, T2, T3, and T4.
Conclusion: The results of this study showed that pre-operative melatonin administration could modify inflammatory cytokines secretion such as IL-6 while it has no significant effect on the serum levels of IL- 9. Neither of the changes was clinically significant.