TNF and atrial fibrillation: Cytokine levels of IL-2, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IP-10, TNF-α, and GM-CSF were not detected in NP and AF tissues of this study, consistent with downregulated gene expression levels of IL-2, IL-6, IL-10, and TNF-α in herniated canine IVDs [35].