Figure 1

Representative electron micrographs of coronal sections of the rat hippocampus are shown. (A, C, and E) control hippocampus. (B, D and F) lead-exposed hippocampus in rats at weaning that were treated with 0.2% lead acetate during the gestational and lactational periods as described. Abnormal appearance of neurons including irregular shaped nucleus, swollen mitochondria, often vacuolated with disrupted cristae, a large quantity of heterochromatin collected inside the nucleus, demyelination or shrinkage, and denaturation of the myelin sheath were observed. These findings suggest that hippocampal ultrastructures were injured by lead exposure during the early stage of life. Scale bar = 1 μm. NN: normal nucleus; IN: irregular nucleus; SM: swollen mitochondria; VM: vacuolated mitochondria; NM: normal mitochondria; H: heterochromatin; DMS: denaturation of myelin sheath.