OBJECTIVEThe relationship between selenium deficiency and the changes of synaptic structure in the CA3 area of hippocampus were studied in the third generation rats.

METHODSA selenium deficiency model was established by feeding rats with selenium-deficient food. The rats were divided into 4 groups: control (Se+I+), selenium deficiency (Se-I+), iodine deficiency (Se+I-), and both deficient group (Se-I-). The hippocampuses were dissected from the third generation rats on the 21st gestational day and the ultrastructural features of hippocampal synapses were observed with electron microscope. The length of active zone, synaptic curvatures, post-synaptic density (PSD) and synaptic cleft were quantitatively described.

RESULTSCompared with the control, the length of active zone and the thickness of PSD were significantly decreased in Se-I+, Se+I- and Se-I- groups [(261.7 +/- 50.1) nm, (286.7 +/- 41.6) nm and (220.8 +/- 61.6) nm contrast to (312.4 +/- 47.7) nm, P < 0.01], so were the synaptic curvatures in Se-I+, Se+I- and Se-I- groups [(22.9 +/- 6.3) nm, (27.5 +/- 8.6) nm and (25.2 +/- 6.5) nm contrast to (48.1 +/- 12.3) nm, P < 0.01]; the width of synaptic cleft were also decreased significantly in Se-I- [(11.1 +/- 3.3) nm contrast to (16.1 +/- 4.0) nm, P < 0.01].

CONCLUSIONSelenium deficiency might cause changes of neuronal functions at the synaptic level, and furthermore, affect learning and memory.