Primers and polymerase chain reaction (PCR) conditions.

* Primers for β-actin were used for both non-quantitative and real-time PCR. (A) Non-quantitative PCR: the first step of the PCR reaction was at 94°C for 5 min to activate the polymerase, followed by the indicated number of cycles of denaturation at 94°C for 45 s, annealing for 60 s at the indicated temperature for each gene, extension at 72°C for 90 s and an additional extension at 72°C for 5 min after the last cycle. (B) Real-time PCR: the first step was 95°C for 3 min, followed by 45 cycles of denaturation (95°C for 10 s), annealing (10 s at the indicated temperature for each gene) and extension (72°C for 10 s).