The cDNA samples were denatured at 95° C for 10 min, and were then amplified for 40–50 cycles: at 95° C (10 s), at 65° C (15 s), and 72° C (22 s) for β-actin; at 95° C (10 s), at 62° C (15 s), and at 72° C (10 s) for SOCS1; and at 96° C (10 s), at 68° C (15 s), and at 72° C (15 s) for SOCS3. Amplification curves of the fluorescence values versus cycle number were obtained, and a melting curve analysis was then performed. The levels of SOCS1 and SOCS3 expression were determined by normalizing relative to β-actin expression. The forward and reverse primers were as follows: for β-actin, 5'-GTGGGGCGCCCCAGGCACCA-3' and 5'-CTCCTTAATGTCACGCACGATTTC-3' ; for SOCS1, 5'-AGACCCCTTCTCACCTCTTG-3' and 5'-GCACAGCAGAAAAATAAAGC-3' ; and for SOCS3, 5'-CCCGCCGGCACCTTTCTG-3' and 5'-AGGGGCCGGCTCAACACC-3'.