AF	Annulus fibrosus
BMI	Body mass index
EDTA	Ethylenediamine tetra-acetic acid
GAPDH	Glyceraldehyde 3-phosphate dehydrogenase
IQR	Interquartile range
IVD	Intervertebral disc
LDD	Lumbar disc degeneration
LDH	Lumbar disc herniation
M	Methylation
MRI	Magnetic resonance imaging
MS-PCR	Methylation specific-polymerase chain reaction
NP	Nucleus pulposus
NRS	Numerical rating scale
ODI	Oswestry Disability Index
PCR	Polymerase chain reaction
qPCR	Quantitative real-time polymerase chain reaction
SEM	Standard error of the mean
Tm	Melting temperature
U	Unmethylation
VDR	Vitamin D receptor