[Effect factors and mechanisms of borneol's bidirectional regulation on blood-brain barrier permeability]

Abstract

In recent twenty years, there are a lot of studies about the effect of borneol on permeability of blood-brain barrier(BBB); however, it isDODOrt of regular conclusions of effect factors and in-depth analysis of functional mechanisms. The current researching data were collected and analyzed in this paper for illuminating the effect factors and mechanisms of borneol on permeability of BBB.The following conclusions were obtained: five factors about borneol influencing the permeability of BBB. First, opticity activity of borneol had no significant effect on action effects. Second, dose of borneol in the range of 50.00-200.00 mg•kg⁻¹, did not affect the effect direction, but only affect its action intensity either with use alone or combination use. Third, the borneol can increase the permeability of physiological BBB, and decrease the permeability of pathological BBB. Fourth, regardless of using singly or using compatibility with musk, borneol can decrease the permeability of BBB in different brain disease models. Fifth, when used with astragalus, catalpol or puerarin, borneol can increase the permeability of BBB and promote the drugs through BBB in pathological conditions. The target spots and mechanisms of borneol's bidirectional regulation on the permeability of BBB are related to the structure and function of cerebral endothelial cells, the exocytosis effects of P-gp and low pinocytosis internal transport effects. On one hand，borneol can down-regulate P-gp by inhibiting NF-κB to reduce the exocytosis effects of P-gp and promote the blood brain barrier pinocytosis to increase the permeability of BBB; On the other hand，borneol can reduce the degradation of basement membrane of blood vessel and tight junctions by inhibiting the expression of IL-1β, MMP-9 to decrease the permeability of BBB；moreover，borneol has bidirectional regulation effects on blood-brain barrier permeability by influencing the signaling pathways of Ca2+-eNOS-NO, VEGF-eNOS-NO. However, the detailed mechanisms that borneol regulates and controls the permeability of BBB are so complicated, so they shall be further proved and clarified.

Keywords: NO; P-gp; bidirectional regulation; blood-brain barrier; tight junctions; borneol.