Early post-natal, low-level lead exposure increases the number of PSA-NCAM expressing cells in the dentate gyrus of adult rat hippocampus

Neurotoxicology. 2006 Jan;27(1):39-43. doi: 10.1016/j.neuro.2005.05.015. Epub 2005 Sep 15.

Abstract

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.

MeSH terms

  • Administration, Oral
  • Animals
  • Animals, Newborn
  • Biomarkers / analysis
  • Cell Count
  • Dentate Gyrus / cytology
  • Dentate Gyrus / metabolism*
  • Immunohistochemistry
  • Lead / blood
  • Lead / pharmacokinetics
  • Lead / toxicity*
  • Neural Cell Adhesion Molecule L1 / biosynthesis
  • Neural Cell Adhesion Molecule L1 / metabolism*
  • Neurons / metabolism
  • Rats
  • Rats, Wistar
  • Sialic Acids / biosynthesis
  • Sialic Acids / metabolism*
  • Time Factors
  • Tubulin / analysis

Substances

  • Biomarkers
  • Neural Cell Adhesion Molecule L1
  • Sialic Acids
  • Tubb3 protein, rat
  • Tubulin
  • polysialyl neural cell adhesion molecule
  • Lead