[Energy dispersive X-ray analysis in studying the permeability of blood-brain barrier caused by lead in rats].
OBJECTIVE
To observe the changes in permeability of blood-brain barrier caused by lead in rats.


METHODS
Rats were fed with drinking water containing 10 and 30 mg/L of lead for three months. Electron microscopy lanthanum nitrate-tracing and electron probe-energy dispersive X-ray (EDX) analysis were used to observe the distribution of lead in different cells of bilateral sides of capillaries of cerebral cortex and the changes in their permeability.


RESULTS
There was significant difference in blood lead levels between the rats with drinking water of 10 mg/L lead and the controls, but only a peak of lead, L(alpha), could appear in plasmalemma of endotheliaocyte endosurface in capillaries, and no any peak in the basement membrane of endotheliocyte of the outer-side, end feet of astrocytes and axons of neurons. Lanthanum nitrate-tracing showed changes in capillary permeability. But, in those with drinking water of 30 mg/L of lead, peak of lead, L(alpha) and M(alpha) could appear in all cells mentioned above. Meanwhile, lanthanum salt granules, which penetrated the cellular gaps of endothelia and seeped in the basement and its peripheral cells, could be found in certain sites of the capillaries with larger diameters.


CONCLUSIONS
It suggests that the plasmalemma of endotheliocyte endosurface was the initial target in brain, where was affected by lead, and the consecutive endotheliocytes of blood vessels served as a blood-brain barrier to lead, although in a very weak action. A little bit accumulation of lead on the plasmalemma of endotheliocyte endosurface could cause damage in the close junction between endotheliocytes to spread to brain substance, same as the lanthanum tracing showed.
Ruan
S
S
Shanghai Municipal Institute for Occupational Health, Shanghai 200003.
Gu
Z
Z
Yang
Y
Y
D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects*; D001921:Brain / Q000378:metabolism*; D002199:Capillary Permeability; D004577:Electron Probe Microanalysis; D007811:Lanthanum; D007854:Lead / Q000493:pharmacokinetics*; D010539:Permeability; D051381:Rats
D007854:Lead; C016534:lanthanide nitrate; D007811:Lanthanum