Tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and limited nutrition causes changes in expression of genes associated with pain and inflammation. Nucleus pulposus (NP) (A) and annulus fibrosus (AF) (B) were analyzed at the indicated days for nerve growth factor (NGF) expression by using quantitative reverse transcription-polymerase chain reaction (RT-PCR). At 3 days of treatment, NGF is significantly increased in NP and AF. At 10 days after treatment, the expression of NGF in NP was significantly increased but in AF showed a lower expression compared with the control. Expression analysis of TNF-α and IL-1β genes showed decreased expression of TNF-α after treatment in NP (C) and AF (D) tissues. IL-1β showed an increase in expression compared with untreated control. Results are shown as the mean ± standard error for three independent experiments (n = 6 discs/group per experiment). *P <0.05. Ctr., control group; Exp, experimental group; ns, not significant.
Ponnappan et al. Arthritis Research & Therapy 2011 13:R171 doi:10.1186/ar3494