| Objective:To evaluate the improvement of Kangshuai Yizhi Formula I (KYF I) on the ability of learning and memory in normal mice, memory dysmnesia mice and the aged mice, exploring the related mechanism in order to prove its role on learning and memory in brain.Methods:(1) Effect of KYF I on ability of learning and memory in normal mice:mice were divided into 4 groups given distilled water, low-, middle-, and high-dose KYF I, respectively, by gastragavege for 40 successive days. Morris water maze was used to assesse the behavior performances of mice. After it, the activities of ChAT, AchE and MAO in hippocampus were measured by colorimetry. the levels of monoamine neurotransmitters noradrenaline (NE), dopamine (DA) and 5-hydroxytryptamine (5-HT) in hippocampus were also determined by high performance liquid chromatography with electrochemical detection (HPLD-ECD). Then the expression of ChAT in hippocampus was observed by immunohistochemistry and westernblot.(2) Effect of KYF I on learning and memory dysfunction of mice:mice were divided into 5 groups, the control group and the model group were treated with distilled water (10ml/kg), while mice in the low-, middle-, and high-dose KYF I groups were given low-, middle-, and high-dose KYF I, respectively, by gastragavege for 35 successive days. The acute learning and memory dysfunction model was established by injection of scopolamine from day 31, and Morris water maze was used to assess the behavior performance of scopolamine-induced model mice for five days. The activities of ChAT, AchE and MAO in hippocampus were measured by colorimetry. The content of monoamine neurotransmitters NE, DA and 5-HT in hippocampus were also detected by HPLD-ECD.(3) Improvement of KYF I on aged learning and memory impaired mice:the mice of 15-18 momths old were divided into 2 groups:the model group and the KYF I treated group, while the mice of 2-3 months old were selected as the control group. Mice in the KYF I treated group were given optimal-dose KYF I by intragastric administration for 50 successive days, while animals in the control and model groups were treated with distilled water. Then we assayed Morris water maze, and the activities of ChAT, AchE and MAO by colorimetry, and the content of NE, DA and 5-HT in hippocampus were measured by HPLD-ECD. Then the expression of ChAT in neuron of hippocampus was observed by Western blot.Results:(1) The learning ability (the escape latency) in the high-dose KYF I group was better than that in the control group in Morris water maze (P<0.05). Comparing with the control group, the ChAT activity in the high-dose KYF I group was increased (P<0.01), but the AchE activity in that group was decreased. In the high-dose KYF I group, the number of ChAT positive neurons were increased on hippocampus CA1 region and its staining was deeper than that in the control group. Moreover, significant differences were observed between the control group and the high-dose KYF I group in the expression of ChAT through Western blot (P<0.05).(2) Comparing with the model group, the ChAT activity in the control group was decreased, the activities of AchE and MAO in that group were increased, and the levels of NE, DA and 5-HT in hippocampus were also increased. It suggested that a model of memory deficits was established successfully. The learning ability and the memory ability (the frequency across the platform and the staying time at the platform) in the middle-and high-dose KYF I groups were significantly better than those in the model group in Morris water maze (P＜0.01). The ChAT activity and the levels of NE, DA and 5-HT in the high-dose KYF I group were significantly increased, but the activities of AchE and MAO in that group were significantly decreased (P＜0.01).(3) Compared with the control group (mice of 2-3 months old), the activities of ChAT and AchE in model group (mice of 15-18 months old) were reduced, while the MAO activity in model group was increased (P<0.05). It suggested that a model of memory deficits was established successfully. Compared with the model group, the escape latency and the MAO activity in the KYF I treated group were decreased, but the staying time at the platform and the ChAT activity in that group were significantly increased (all P＜0.05).Conclusions:(1) High-dose KYF I can improve the ability of learning and memory in normal mice, which suggested that KYF I stimulated the activity of ChAT, increased ChAT positive cells on hippocampus CA1 region, and enhanced the expression of ChAT in hippocampus, thus, promoting the synthesis of Ach in brain.(2) High-dose KYF I can improve the ability of learning and memory, related to the central cholinergic system and the hippocampal monoamine neurotransmitters, in model mice induced by scopolamine.(3) KYF I can prevent and cure learning and memory impairment in aged mice. The results suggest that KYF I can elevate the synthesis of Ach by enhancing the ChAT activity, and it can also regulate monoamine neurotransmitters by inhibiting the MAO activity.
|
PDF Full Text Request