A Comparative Study Of Blood-brain Barrier And Blood-nerve Barrier Endothelial Cell Properties

Background and ObjectiveWith the increase of the incidence and the life-span of patients with diabetes,the diabetic neuropathy has received much attention recently.However,until now the mechanisms of it are not clear.Recently,a variety of structural abnormalities of microvessels have been found in diabetes and diabetic neuropathy.On the other hand, there is evidence from clinical observe that peripheral neuropathy occurs in approximately 94%of diabetic neuropathy,but CNS damage is rare.Perhaps these are associated with the difference in microvascular property between brain and peripheral nerve.Some scholars had noticed that there is a physiological difference between BBB and BNB microvessels,the ionic permeability of BBB microvessels is lower than that of BNB.So it is important to further study BBB and BNB microvessels.Recently,it is found that the BBB endothelium can immunohistochemically be defined by its expression of specific membrane proteins,so-called BBB markers.Most of these are proteins involved in regulating the passage of substances through the capillary wall, e.g,the OX-26,EBA,OX-47,γ-GGT.A comparative study of BBB and BNB microvascular property can be dong by BBB markers.The investigation of the BBB and BNB properties may provide some experimental data and theoretical basis for the prevention and treatment of the diabetic neuropathy.MethodsThe rat brain cortex and sciatic nerve were removed,Ultrastructure of endothelial cell was observed by electron microscopy.Employing immunohistochemical(IHC) staining the relative distribution was determined for the OX-26,OX-47,EBA and extravasated fibrinogen around microvessels.Theγ-glutamy transpeptidase(γ-GGT) are revealed by using enzyme cytochemistry.ResultsMicrovessels both in BBB and in BNB did share the same tight junctions.however,BNB had a significantly higher number of vesicles than that of BBB.By immunocytoehemistry and enzyme Cytochemistry,microvessels in BNB showed no expression of the OX-26,OX-47,EBA andγ-GGT,but staining weakly positive for fibrinogen;microvessels in BBB showed strong positive for OX-26, OX-47,EBA andγ,-GGT,marked perivascular staining of fibrinogen was not seen.ConclusionsTight junctions were present in both BBB and BNB endothelial cell.however,there was a significant difference between them in the number of the pinocytotic vessels, markers expression and permeability.BNB lacked the typical BBB characteristics.