The BAX/BCL2 ratio in the IVDs (NP and AF) treated with 250 μg rhBMP-7 was significantly upregulated compared with the IVDs (NP and AF) treated with the sham and 25 μg rhBMP-7, suggestive of an anti-apoptotic effect of 250 μg rhBMP-7. Here, BAX is linked to atrial fibrillation.