Abstract: Objective To investigate the difference of endothelial cell (EC) in ultrastructure,markers and permeability between blood-brain barrier (BBB) and blood-nerve barrier (BNB).MethodsThe rat brain cortex and sciatic nerve were removed.Ultrastructure of endothelial cell was observed with electron microscopy.Employing immunohistochemical (IHC)staining,the relative distribution was determined for the OX-26,endothelial barrier antigen (EBA)and extravasated fibrinogen around microvessels.ResultsMicrovessels both in BBB and in BNB did share the same tight junctions.However,BNB had a significantly larger number of vesicles than that of BBB.Microvessels in BNB did not express the OX-26 and EBA,but staining weakly positive for fibrinogen,while microvessels in BBB showed strong positive for OX-26 and EBA,perivascular staining of fibrinogen had not been seen.ConclusionTight junctions were present in both BBB and BNB endothelial cell,but there was a significant difference between them in the number of the pinocytotic vesicles,markers expression and permeability.

Key words: blood-brain barrier, blood-nerve barrier, ultrastructure, immunohistochemistry