Fig. 2. Quantification of invasion efficiency of bacteria in bovine aortic endothelial cells using real-time polymerase chain reaction assay. The cells were incubated with or without treatments for 24 h and then incubated with bacteria at multiplicity of infection of 100:1 for 2 h. The control was untreated cells and the negative control was DNA of bovine aortic endothelial cells (BAECs). (A) A standard curve was constructed via 10-fold serial dilutions of the extracted genomic DNA of the bacteria from 2.7 × 10² to 2.7 × 10⁻³ ng. (B) Quantification of bacterial number per cell in different treatments of BAECs. Invasion efficiency is expressed as the bacterial number/BAEC. Data are presented as mean ± SD of two independent assays with at least three replicate samples each. Significant difference from untreated cells indicated by ^**p < 0.01, ^***p < 0.001 (Turkey's honest significant difference test, one-way ANOVA). CFU, colony-forming unit; LPS, lipopolysaccharide; DEXA, dexamethasone.