LAUSR

To evaluate the immunomodulatory effect of minocycline, the present study was carried out on the gene expression of toll-like receptor type-4 (TLR4) and some pro-inflammatory (IL-1β, IL-6) and anti-inflammatory cytokines (IL-10) associated with lipopolysaccharide (LPS) -induced inflammation in human peripheral blood mononuclear cells (PBMCs). The PBMCs were collected and then 5.4 × 106 PBMCs/mL were used in eight groups as follows: control group (only media), LPS group (only LPS), methylprednisolone (Pred) group (LPS plus Pred), meloxicam (Melo) group (LPS plus Melo), three minocycline groups [M1, M5 and M25] (LPS plus 1, 5, and 25 µg/mL minocycline, respectively) and minocycline control (MC) group (5 µg/mL minocycline). After incubation for 24 h, the PBMCs were subjected to quantitative PCR assays. Gene expression levels of TLR4 were not changed in any groups. The IL-1β levels were increased in the LPS group but the increases were much more intense in the other groups except Pred group. Compared with control group, IL-6 levels increased significantly in Melo, M1 and M25 groups. Significant increases of IL-10 levels were also observed in Melo, M25 and MC groups. It can be concluded that minocycline had dual pro- and anti-inflammatory activities with potential clinical immunomodulatory effects.