Annulus Fibrosus Cells (AFC)

Annulus fibrosus, located in the intervertebral disc peripheral portion, consisting of a fiber cartilage, annulus fibrosus fiber in lumbar oblique, on the transverse section arranged in concentric ring, ring adjacent to the fiber with opposite inclination, and cross each other. Fiber ring is divided into outer, middle and inner layer of three concentric circles of fiber structure. The outer layer is mainly collagen fiber. Annulus Fibrosus Cells (AFC) can affect the local degradation and inflammatory process by stimulation of interleukin 1β（IL1β), 17β-Estradiol has been reported to protect annulus fibrosus cells in vitro against interleukin-1β (IL1β)-induced apoptosis in a concentration-dependent manner. Annulus fibrosus cells are identified by immunocytochemistry of type I collagen. AFC is an in vitro model of intervertebral disc degeneration from the perspective of cell and molecular events.