Inflammation in the intervertebral disc herniation.

Up until fairly recently, it was thought that sciatic pain in the lumbar herniated disc was caused by compression on the nerve root. However, the lumbar herniated disc shows mixed pictures which are difficult to explain by simple mechanical compromise. In recent years various immunology, immunohistochemistry and molecular biology studies have shown that the herniated tissue is not an inert material, but rather it Is biologically very active with the capability of expressing a series of inflammatory mediators: cytokines such as interleukin-1, interleukin-6, interleuquin-8 and tumor necrosis factor being the ones which stand out. The inflammation is not only induced by the chemical irritation of the bioactive substances released by the nucleus pulposus but also by an autoimmune response against itself. Thus, in addition to the mechanical factor, the biomechanical mediation plays an important role in the pathophysiology of sciatic pain and of radiculopathy. Through a review of a wide range of literature, we researched the cellular molecular mediators involved in this inflammatory process around the lumbar herniated disc and its involvement in sciatic pain.