Toxic Effects of Low Level Lead on the Blood-Brain Barrier in Rats

Toxic Effects of Low Level Lead on the Blood-Brain Barrier in Rats: Su-yun RUAN, et al. Shanghai Institute of Labour Hygiene and Occupational Diseases—This study was designed to invest igate damage to the permeabi l i ty and ultrastructure of the blood-brain barrier caused by low level lead by using Lanthanum nitrate tracing and to explore the blood and the brain lead threshold level which induced such damage. The results showed that there was no obvious damage to the blood-brain barrier in the 10 mg/L lead exposure group when the blood lead level reached 1.67 times as high as that in the control group, and the brain lead level was not much higher than that in the control group. But in the 30 mg/ L lead exposure group, when the blood and brain lead levels reached 2.46 and 1.34 times that in the control group, respectively, lanthanum granules seeped into the base membrane and pericytes through the space between neighbouring endotheliocytes. The results suggested that the damage in close junctions between endotheliocytes was an early and easily observable brain marker of exposure to low level lead. In animal experimentals the lanthanum nitrate tracing technique with cardiac flush fixation is a sensitive and effective method for revealing changes in the permeability of the blood-brain barrier. It can be used in experiments on lead or other toxic environmental pollutants affecting the blood-brain barrier, and also in observing the effects of new preventive and therapeutic medicaments. (J Occup Health 1999; 41: 39–42)