Integrin α7 regulates the development of the myodural bridge complex in rats

Abstract

The myodural bridge (MDB) is a fibrous structure that connects the suboccipital musculature to the cervical spinal dura mater (SDM) via the atlanto-occipital and atlanto-axial interspaces. Muscles, ligaments, and MDB fibers integrated a functional unit known as MDB complex (MDBC). MDB is an evolutionarily conserved physiological structure that is considered as a dynamic source of cerebrospinal fluid circulation. Integrin α7 (ITGA7) plays a crucial role in transmitting both longitudinal and lateral forces generated by muscle contraction. To explore the molecular mechanism and the force transmission role of MDB, shRNA-ITGA7 lentivirus vectors were injected into the rectus capitis dorsal minor (RCDmi) of neonatal rats. Inhibition of ITGA7 expression led to muscle dystrophy and an increase in loose and lacked directionality MDB fibers in the atlanto-occipital interspace. Collagen fibers displayed varying thicknesses and formed interlaced clusters. Numerous fibroblasts remained interspersed among the MDB fibers. Inhibition of ITGA7 expression impedes MDBC development and formation. The study indicates that suboccipital muscle stress influences MDB fiber differentiation and maturation, confirming the role of MDB in transmitting this stress to SDM and in cerebrospinal fluid circulation. Additionally, the study highlights the significance of ITGA7 as a pivotal regulator in MDBC development.