Effects of Notch signaling activation on expression of matrix catabolic and anabolic genes in chondrogenic ATDC5 cells. (a–d) qPCR analyses of Notch signaling target genes (a), matrix anabolic genes (b), and matrix catabolic genes (c,d) in ATDC5 cells infected with Ad-GFP or Ad-NICD1 for 3 days. Relative gene expression was calculated by 2−ΔΔCt method after normalizing first to house-keeping Gapdh, and then to the control groups (Ad-GFP-infected cells). Data are means ± SD. *p <0.05, n = 3. (e) Western blot analysis of Mmp13 in ATDC5 cells infected with Ad-GFP or Ad-NICD1 for 3 days