Progress of researches on mechanisms of acupuncture therapy in the treatment of lumbar disc herniation.

Lumbar intervertebral disc herniation (LDH) is a common and frequently-occurring disease, which usually causes lumbar and leg pain. Studies have shown that acupuncture can improve the symptoms of LDH patients. In the present paper, we summarize the progress of researches on the mechanisms of acupuncture underlying improvement of symptoms of LDH in recent 10 years from 1) delaying the intervertibral disc degeneration (by down-regulating the expressions of matrix metalloproteinase ［MMP］-3 and MMP-4, up-regulating the expressions of diosaccharides and polyglycoprotein, inhibiting apoptosis and promoting mitochondrial autophagy of nucleus pulposus cells, etc.), 2) maintaining spinal column stability (by relieving rachiasmus and improving lumbar flexor and extensor muscle strength, lowering the degree of polyfidus edema and fat infiltration, and restoring the biomechanics of the spine), 3) regulating inflammation (by inhibiting the production of proinflammatory factors and increasing the production of anti-inflammatory factors, etc.), 4) regulating immune response (by promoting the activity of T cells and other immune cells, lowering serum levels of MMP-3, transforming growth factor-β1 and prostaglandin E2, raising serum levels of IgA, IgG and IgM to improve immune function ), 5) modulating neural structure and function (by promoting myelin regeneration of sciatic nerve fibers, and reducing the edema of Schwann cells' cytoplasm and mitochondria, and improving neural ultrastructure, and sensory and motor functions of peripheral nerves, etc.), 6) relieving lumbar pain (by down-regulating expression of Ca²⁺/calmodulin-dependent protein kinase and activation of lumbar spinal cord glial cells, blocking nociceptive signal conduction, regulating the levels of pain-related factors, etc.), and 7) improving local microcirculation. These results may provide scientific evidence for acupuncture treatment of LDH.