[Protection of zinc on hippocampal cholecystokinin of lead-exposed rat].
OBJECTIVE
To investigate the relationship between the effects of zinc on hippocampal cholecystokinin (CCK) positive neurons and learning and memory ability of lead-exposed rats.


METHODS
Thirty-six Wistar rats were divided into control group, lead-exposed group (drunk 6.15 mmol/L of lead solution) and lead-zinc group (drunk 6.15 mmol/L of lead + 3.10 mmol/L of ZnSO(4) solution) randomly. Y-maze test was used to study learning and memory ability in rats; Atomic absorption method was used to determine serum and hippocampal lead content; ABC immunohistochemistry and quantitative graphic analysis were used to investigate the changes of CCK positive neurons in different hippocampal subfields in lead-exposed rats.


RESULTS
The learning and memory ability in lead-exposed rats were significantly lower (P < 0.05) while the serum and hippocampal lead content in lead-exposed rat were significantly higher (P < 0.05) than those in control and lead-zinc group. The number and optical density of CCK positive neurons in CA(1) and CA(3) areas of lead-exposed rats were significantly lower (P < 0.05) than those in control and lead-zinc group. No differences in these indexes between the control and lead-zinc group were found (P > 0.05).


CONCLUSIONS
Lead may damage the learning and memory ability and affect the number of CCK positive neurons in lead-exposed rats. Zinc might play an important role in preventing lead-induced damages.
Li
Ji-Sheng
JS
Institute of Military Preventive Medicine, Medical College of Chinese Police Forces, Tianjin 300162, China.
Yan
Bei
B
Zhao
Xin
X
Liu
Ya-Hua
YH
D000818:Animals; D002766:Cholecystokinin / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007854:Lead / Q000633:toxicity*; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015032:Zinc / Q000494:pharmacology*
D007854:Lead; D002766:Cholecystokinin; D015032:Zinc