Neuroprotective Effect of Lucium chinense Fruit on Trimethyltin-Induced Learning and Memory Deficits in the Rats

Abstract

In order to the neuroprotective effect of Lycium chinense fruit (LCF), the present study examined the effects of Lycium chinense fruit on learning and memory in Morris water maze task and the choline acetyltransferase (ChAT) and cyclic adenosine monophosphate (cAMP) of rats with trimethyltin (TMT)-induced neuronal and cognitive impairments. The rats were randomly divided into the following groups: naïve rat (Normal), TMT injection+saline administered rat (control) and TMT injection+LCF administered rat (LCF). Rats were administered with saline or LCF (100 mg/kg, p.o.) daily for 2 weeks, followed by their training to the tasks. In the water maze test, the animals were trained to find a platform in a fixed position during 6d and then received 60s probe trial on the 7(th) day following removal of platform from the pool. Rats with TMT injection showed impaired learning and memory of the tasks and treatment with LCF (p<0.01) produced a significant improvement in escape latency to find the platform in the Morris water maze at the 2(nd) day. Consistent with behavioral data, treatment with LCF also slightly reduced the loss of ChAT and cAMP in the hippocampus compared to the control group. These results demonstrated that LCF has a protective effect against TMT-induced neuronal and cognitive impairments. The present study suggests that LCF might be useful in the treatment of TMT-induced learning and memory deficit.

Keywords: Lycium chinense fruit (LCF); choline acetyltransferase (ChAT); cyclic adenosine monophosphate (cAMP); trimethyltin (TMT).

Fig. 1

(A) The latency to escape onto the hidden platform during the Morris water maze. The task was performed with 3 trials per day during 6 days for the acquisition test. The values are presented as means±S.E.M. ^*p<0.05 vs. normal group & ^#p<0.05 vs. control group, respectively. (B) Retention performance was tested on 7th day. The rats received a 1 min probe trial in which the platform was removed from the pool for retention testing. The values are presented as means±S.E.M. ^*p<0.05 vs. normal group & ^##p<0.01 vs. control group, respectively.

Fig. 2

The number of choline acetyltransferase (ChAT) immunostained nuclei in different hippocampal CA1 and CA3 of the experimental groups. Each values represents the ±S.E.M.

Fig. 3

The number of cyclic adenosine monophosphate (cAMP) immunostained nuclei in different hippocampal CA1 and CA3 of the experimental groups. Each values represents the ±S.E.M.