Immunomodulatory Potential of Melatonin in Immunosuppression: An in-vivo Study.

Objective: To assess the immunomodulatory effects of melatonin on the acquired immunity of immunosuppressed male Wistar rats by checking Interleukin 6 (IL-6) levels, total leucocyte counts (TLC), and differential leucocyte counts.

Study design: Experimental study. Place and Duration of the Study: Animal laboratory, CMH Lahore Medical College, from June to October 2023.

Methodology: Fifty male Wistar rats, weighing 180g to 200g, were included in this study with 10 rats in each of the five groups namely cyclophosphamide (CP), CP + melatonin, CP + immunomodulator, melatonin-only, and control. A calculated dose of CP was administered intraperitoneally for 30 days (from 13/06/23 to 13/07/23) to each group except the control groups. After this, the experimental group was given melatonin CP + Melatonin for 7 days (from 14/07/23 to 20/07/23). CP + Immunomodulatory group was kept for comparison of immunomodulatory effects. Blood samples were drawn from all 5 groups. IL-6 was estimated through ELISA. Other parameters assessed were TLC and absolute differential leucocyte counts.

Results: Melatonin increased IL-6 levels significantly (p = 0.042) as well as the TLC levels (p <0.001) compared to the immuno-suppressed CP group. Melatonin was seen to have an upregulation of IL-6 levels in immunosuppression compared to the administration of immunomodulator preparation (p = 0.506) which was not as effective. Administration of melatonin significantly increased the TLC, neutrophil, lymphocyte, monocyte, and eosinophil count compared to known immunomodulators.

Conclusion: Melatonin as a supplement may have some role in activating multiple immune response processes in immune-depressed states. It was also established that it allows quick recovery of cell components from immunosuppressed states.

Key words: Melatonin, Immunomodulation, Rats, Interleukin-6, Acquired immunity, Cyclophosphamide.