Effect of cornel iridoid glycoside on learning-memory ability and synaptophysin in fimbria-fornix transacted rats

DING Yue-xia; ZHANG Li; YE Cui-fei; WANG Wen; LI Lin

Abstract：Objective: To investigate the effect of cornel iridoid glycoside(CIG) on learning-memory abili-ty and its mechanisms in rats with brain injury. Methods: Mechanical brain injury was induced by fimbria-fornix transaction(FFT) in rats. After the operation, rats were administered by intragastric CIG(20, 60 and 180 mg· kg~(-1)) for 21 days. The learning and memory abilities were determined by the step-through test and Morris water maze test. Then the brain was immediately removed, and the expression of hippocampal synaptophysin(SYP) was detected by immunohistochemistry and Western blotting. Results: In the step-through test, the FFT rats showed shorter latency as compared with the sham-operated rats(P < 0.01). Intragastric CIG(60 and 180 mg·kg~(-1)) sig-nificantly prolonged the latency of FFT rats (P < 0.05). In the Morris water maze test, the escape latency in FFT rats was significantly longer than that in sham-operated rats(P <0.01) , and CIG(20 and 60 mg·kg~(-1)) obviously shortened the escape latency of FFT rats(P <0.05, P < 0.01). Both immunohistochemistry and Western blotting showed that the expression of hippocampal SYP in FFT rats was significantly lower than that in sham-operated rats (P <0.01). CIG(20, 60 and 180 mg·kg~(-1)) obviously elevated the expression of SYP in the hippocampus of FFT rats(P < 0.05, P < 0.01). Conclusion : Intragastric administration of CIG markedly improved learning-memory a-bility in FFT rats, and one of the mechanisms may be related to elevating hippocampal SYP expression and thus promoting synapses restitution.