Objective: To study the effect of learning and memory ability on lead poisoning mice treated by lentinan and calcium disodium edetate

and to explore the mechanism preliminarily. Method: Fifty mice were randomly divided into five groups

control group

model group

positive control group

lentinan low dose group and high dose group. The mice in the control group were given intraperitoneal injection of saline at the same dosage

and the mice in other groups were given intraperitoneal injection of 2%Pb (Ac)2 solution (70 mg·kg-1) for 8 days. Then the mice in the control group and model group were given intraperitoneal injection of saline at the same dosage for seven days

and the mice in other groups were given intraperitoneal injection of calcium disodium edetate(80 mg·kg-1) for three days

at the same time the mice in lentinan low dose group and high dose group were given intraperitoneal injection of lentinan(1.5 mg·kg-1 and 3.0 mg·kg-1) for seven days. Step-down test and Morris water maze were used to monitor the learning and memory ability. In the mean time

the activity of choline acetyltransferase(ChAT) and ture choline esterase(TChE) was measured by biochemical methods.And the alterations in hippocampus slices morphology were assessed using microscope. Result: The learning and memory ability of lead poisoning mice could be markedly improved by lentinan high dose group. Compared with model group

the escape latency of mice in lentinan high dose group was markedly shortened(P<0.01)

and the retention latency of mice was markedly lengthened(P<0.01)

and the fault numbers were markedly reduced(P<0.01). The activity of ChAT was markedly decreased(P<0.01) and TChE was markedly increased (P<0.01).The degenerative changes of neuron in hippocampus slices were improved.Compared with positive control group. the escape latency of mice in lentinan high dose group was shortened(P<0.05)

and the retention latency of mice was markedly lengthened(P<0.01)

and the fault numbers were markedly reduced(P<0.01). The activity of ChAT was markedly decreased(P<0.01) and TChE was markedly increased (P<0.01). Conclusion: The combined application of lentinan and calcium disodium edetate could improve the learning and memory ability in lead poisoning mice. The mechanism may be related to increasing the activity of ChAT and decreasing the activity of TChE and the improvement of the function of the central cholinergic system.