Polymerase chain reaction (PCR) and real-time PCR were performed using primers after reverse-transcription of total RNAs, as previously described (Heo et al., 2014 (link)) PCR was performed using Taq PCR Kit (New England Biolabs Ltd., Ipswich, MA). The cDNA was denatured at 90°C for 5 min followed by 25 cycles of PCR (95°C for 30 sec, 55°C for 30 sec, 72°C for 30 sec). In the analysis, transcript of glyceraldehydes-3-phosphate dehydrogenase (GAPDH) was amplified as an internal control. Real-time quantitative PCR was performed in triplicate using the LightCycler 96 Real-Time PCR System (Roche, Germany); each 20-μl reaction consisted of 10 μl of SYBR Green Master Mix, 2 μl of forward and reverse primers (10 pM each) of genes to be analyzed, and cDNA template. Thermal cycling conditions were as follows: 95°C for 10 min, and 45 cycles at 95°C for 10 sec, 50°C for 10 sec, and an elongation period for 10 sec at 72°C. The relative expression of each gene was then calculated as a ratio to GAPDH using LightCycler 96 software (Version 1.1.0.1320). Primers for glyceraldehydes-3-phosphate dehydrogenase (GAPDH) were 5-GAGTCAACGG ATTTGGTCCT-3 (forward) and 5-TGTGGTCATGAGTCCTTCCA-3 (reverse). Primers for IL8 were 5-TCTGCAGCTCTGTGTGAAGG-3 (forward) and 5-AATTTCTGTGTTGGCGCAGT-3 (reverse).