Blood-nerve barrier: Structure and opening

Abstract

Like the blood-brain barrier and blood-spinal cord barrier, the blood-nerve barrier (BNB) is one of the crucial tissue barriers of the nervous system. It plays a vital role in homeostasis, physiological protection, and pathological reactions. Various factors, such as biological, physical, and chemical factors, can lead to transient or permanent dysfunction of the BNB. With the advancements in biological techniques and the growing peripheral nerve injuries such as trauma and diabetic peripheral neuropathy, the BNB has gained increasing attention. Moreover, the defensive function of the BNB impedes therapeutic deliveries and anesthetic drugs, which compromises the therapeutic experiences and life quality. It should be noted that numerous pathways are involved in the microstructure, function, and opening of the BNB, but the true underlying molecular mechanisms are still under constant exploration and investigation. This review summarizes the microstructure, and signaling pathways of the BNB, and thoroughly discusses the transient or permanent disruptions of the BNB in both physiological and pathological conditions.