[The effects of testosterone on the expression of inflammatory factors in 3T3-L1 adipocytes and its mechanism].

OBJECTIVE:To explore the effects of androgen upon the production of inflammatory Cultured factors in 3T3-L1 adipocytes and to investigate the mechanism at the molecular level. METHODS:pre-adipocytes from 3T3-L1 cell line were induced to differentiate into adipocytes. Mature adipocytes were treated with testosterone at a concentration of 10(-9) to 10(-15) mol/L for either short (0 to 30 min) or long (12, 24 and 48 h) treatment course. Secretion of inflammatory factors, i.e., interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1), in the culture medium were determined by enzyme-linked immunosorbent assay (ELISA). The mRNA expression of IL-6 and MCP-1 were determined by reverse transcriptase PCR. Phosphorylation of NF-KB was analyzed by Western blot with beta-actin as the reference gene. In another experiment, adipocytes were manipulated according to the same protocol except being pretreated with PDTC (inhibitor of NF-KB) for 2 h prior to the addition of testosterone. The results of two experiments were compared. RESULTS:(1) The secretion of IL-6 and MCP-1 in the culture medium were higher in the testosterone-treated groups than in the control groups (P < 0.05). The highest concentration of IL-6 and MCP-1 were observed in the group treated with 10(-5) M testosterone for 24 h. The mRNA expression of IL-6 and MCP-1 were higher in the groups treated with testosterone for 12 h, especially with testosterone of 10(-5) mol/L; (2) With a short treatment course of testosterone, more NF-kappaB were phosphorylated than in control, especially with testosterone of 10(-5) mol/L. More NF-kappaB was phosphorylated following the 12 h testosterone treatment (10(-9), 10(-7) and 10(-5) mol/L), especially with a testosterone concentration of 10(-9) and 10(-5) mol/L. (3) When pretreated by NF-kappaB inhibitor and followed by 10(-5) mol/L testosterone for 24 h, the secretion of IL-6 and MCP-1 in the culture medium decreased significantly (P < 0.01). Likewise, when pretreated by NF-kappaB inhibitor and followed by 10(-5) M testosterone for 12 h, the mRNA expression of IL-6 and MCP-1 decreased significantly. CONCLUSION:Within the certain scope, testosterone could increase the expression of inflammatory factors in adipocytes through the activation of NF-kappaB.