mRNA expressions of peroxisome proliferator-activated receptor gamma coactivator 1α, tumor necrosis factor-α, and interleukin-6 in paraspinal muscles of patients with lumbar kyphosis: a preliminary study

BACKGROUND: Kyphosis is a spine deformity that can lead to falls and reduced quality of life. Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) regulates mitochondrial biogenesis and is important for proper functioning of skeletal muscle, including the paraspinal muscles, which support and allow movement of the spine. The role of PGC-1α in paraspinal muscles in lumbar kyphosis has not been examined. We also examined the expressions of the proinflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6. METHODS: We obtained paraspinal muscle specimens from 12 patients who underwent posterior lumbar surgery. RNA was isolated from these samples, and quantitative PCR was performed to compare the expression levels of PGC-1α, TNF-α, and IL-6 mRNA between patients with decreased lumbar lordosis (LL) and normal LL patients. RESULTS: TNF-α and IL-6 mRNA expressions in paraspinal muscles were significantly higher in the decreased LL group than in the normal LL group (P=0.048 for both). PGC-1α mRNA expression was slightly increased in the decreased LL group, but the difference was not significant. Age was significantly positively correlated with PGC-1α mRNA expression (P=0.010). PGC-1α mRNA expression was significantly positively correlated with TNF-α mRNA expression (P=0.022). LL was significantly negatively correlated with PGC-1α, TNF-α, and IL-6 mRNA expressions (P=0.015, 0.036, and 0.010, respectively). CONCLUSION: TNF-α and IL-6 mRNA expressions in paraspinal muscles were significantly higher in the decreased LL group than in the normal LL group. LL was significantly negatively correlated with PGC-1α, TNF-α, and IL-6 mRNA expressions. PGC-1α mRNA expression levels in paraspinal muscles may be affected by lumbar kyphosis.