CXCL1 and infection: Melatonin treatment (30 nM) reduced the levels of IL-6 (2-fold), MCP-1/CCL2 (5-fold), and RANTES/CCL5 (6-fold) compared to vehicle treatment after both 4 and 24 h of infection, while both vehicle and melatonin treatment reduced the levels of IL-10, MIP-2/CXCL2, and KC/CXCL1 (Figure 3).