OBJECTIVE To investigate the role of chemokine CCL2 in leaning memory in rats and the mechanism of hippocampal neuronal apoptosis.METHODS Stereotaxic technique was used in this study to infuse CCL2(0.5,5 and50 ng) into bilateral hippocampus,sham group was received the equal volume of sterile saline.Morris water maze(MWM) was employed to assess the learning and memory ability of rats.Quantitative real-time PCR(RT-PCR) was used to detect the relative expression of caspase 3,Bax and Bcl-2 in hippocampus.RESULTS The results of the place navigation task showed that compared to the sham group(18.66±0.82) s,the latency in each model groups [24.18±1.08,25.99±1.96,(28.67±1.47) s] were significantly extended(P<0.05) while the swimming speed have no difference.In probe trial,the crossing times of each model groups [2.86±0.59,2.89 ±0.39,(2.50±0.37) s] were shorter than sham group(4.50±0.76) s(P<0.05).The result of RT-PCR showed that the relative expression of caspase 3 in CCL2 5 ng group(1.275±0.078)and CCL2 50 ng groups(1.283±0.043) in higher than sham group(1.000±0.000),as the same as Bax(1.107±0.028,1.096±0.015).Yet the relative expression of Bcl-2 has no significant difference among groups.CONCLUSION CCL2 may impaired learning and memory in rats in dose-dependent manner.The effect to induce hippocampal neuronal apoptosis may mediated by caspase 3 activation and Bax regulation.
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