We recently showed that alcohol significantly suppressed lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-α) production by whole blood and total mononuclear cells from healthy subjects as measured by bioassay. In the current study, we further examined the effect of alcohol on LPS-induced TNF-α gene expression by semiquantitative solution PCR and in situ reverse transcriptase PCR (RT-PCR) hybridization methods. Peripheral blood mononuclear cells were cultured with LPS (10 μg/ml) for 4 to 8 h with or without different concentrations of ethanol (0.1, 0.2, and 0.3% [vol/vol]). Total RNA from treated and untreated cultures was extracted and used for solution PCR analysis. Treated and untreated cells were subjected to both conventional in situ hybridization and RT-PCR in situ hybridization. In solution RT-PCR in vitro analysis, alcohol significantly suppressed TNF-specific message. In conventional in situ hybridization, the effect of alcohol on TNF-α gene expression was poorly detected. However, when cells were subjected to RT-PCR prior to in situ hybridization, cells treated with alcohol significantly suppressed expression of the message for TNF-α. These studies confirm our earlier finding that alcohol suppressed the production of TNF-α by LPS-induced whole blood cells and peripheral blood mononuclear cells. Furthermore, these studies also demonstrate that the RT-PCR in situ technique is a powerful tool for detecting and amplifying specific genes in whole cells when limited numbers of cells are available for RNA extraction.
