... Rats (cm3) ADNULL (2. 8×1010 particles) 0 0 ADhBMP6 (2. 8×1010 particles) 1. 02 0.07 0.08±0. 02 ADrBMP6 (2. 8×1010 particles) 0.48±0.09 0 ADrBMP-6 (1.4×1011 particles) 1.06±0.05 ... According to previous studies, BMPs combine with type 1 (Alk2, Alk3, and Alk6) and type 2 (BR2, ActR2, and ActR2B) receptors, activate the Smad and p38/MAPK signal transduction pathways, and, finally, ... 1010 particles/50 µl for all BMP4 vectors (upper panel), 2. 8 × 1010 particles/50 µl for ADhBMP6 and 1.4 × 1011 particles/50 µl for ADrBMP6 (lower panel), and 5 × 1010 (upper panel) and...