CCL2 and obesity due to melanocortin 4 receptor deficiency: Above all, melatonin relieves inflammation and subsequently improves the systemic inflammatory state following obesity [178], mainly owing to its role in the upregulation of anti-inflammatory cytokines and downregulation of pro-inflammatory cytokines [179], such as leptin, interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-α (TNF-α) [22,36].