Early post-natal, low-level lead exposure increases the number of PSA-NCAM expressing cells in the dentate gyrus of adult rat hippocampus.
Although lead is widely known as a potent neurotoxin, the effect of lead exposure on the expression of the polysialic acid linked neural cell adhesion molecule (PSA-NCAM) remains unclear. We exposed Wistar rat pups to 0.2% lead acetate from postnatal day (PND) 1 to PND 30. This exposure protocol resulted in pup blood lead levels, which increased to 29.3+/-5.0 mg/dl on PND 15, and subsequently rose to 34.2+/-5.8 mg/dl at weaning. Corresponding brain tissue lead levels were 456+/-23 ng/g on PND 15 and 781+/-87 ng/g on PND 30. Animals were sacrificed on PND 80, when the blood and brain lead concentrations did not differ from those of the control group. Lead exposure induced a significant increase in the total number of PSA-NCAM expressing cells, compared to the control group (p<0.01), and did not change the proportion of cells co-expressing PSA-NCAM with glial or neuronal markers (calbindin, TuJ1, GFAP). These results suggest that early post-natal lead exposure induces persistent changes in the number of PSA-NCAM expressing cells, which could be, at least, partly the basis of impairments in the learning and memory formation, which follows low-level lead exposure.
Heidmets
Lenne-Triin
LT
University of Tartu, Department of Pharmacology, 19 Ravila Street, 51014 Tartu, Estonia.
Zharkovsky
Tamara
T
Jurgenson
Monika
M
Jaako-Movits
Kulli
K
Zharkovsky
Alexander
A
D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers / Q000032:analysis; D002452:Cell Count; D018891:Dentate Gyrus / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D007854:Lead / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D039842:Neural Cell Adhesion Molecule L1 / Q000096:biosynthesis / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012794:Sialic Acids / Q000096:biosynthesis / Q000378:metabolism*; D013997:Time Factors; D014404:Tubulin / Q000032:analysis
D015415:Biomarkers; D039842:Neural Cell Adhesion Molecule L1; D012794:Sialic Acids; C488416:Tubb3 protein, rat; D014404:Tubulin; C103469:polysialyl neural cell adhesion molecule; D007854:Lead