Repetitive intermittent hyperglycemia (RIH) promotes the expression of TLR4 on THP-1 macrophages. THP-1 transformed macrophages were cultured for 3 days under conditions of hypoglycemia (3 mM/L), normoglycemia (5 mM/L), persistent medium hyperglycemia (15 mM/L), and RIH/glucose fluctuations (3–15 mM/L). Cells were harvested and stained with fluorescent antibodies against CD14 and TLR4 along with isotype matched controls. TLR4 gene expression were measured using real-time qRT-PCR as described in the Materials and Methods section. (A) Representative flow cytometry data from three independent determinations with similar results are presented as dot blot for TLR4 vs. CD14 expression in macrophages. (B) Representative flow cytometry data from three independent determinations with similar results are presented as bar graph of mean staining index (SI). (C) Representative qRT-PCR data from three independent determinations with similar results are presented as bar graphs showing TLR4 gene expression as fold change over control gene expression taken as 1. All data are expressed as mean ± SEM values. ** p ≤ 0.01, **** p ≤ 0.0001, and NS: nonsignificant.