RESUMO
<p><b>OBJECTIVE</b>To explore the effects of Yizhi Capsule (YZC) on learning and memory disorder and beta-amyloid peptide induced neurotoxicity in rats.</p><p><b>METHODS</b>Various doses of YZC were administered to Sprague-Dawley (SD) rats for 8 consecutive days, twice a day. On the 8th day of the experiment, scopolamine hydrobromide was intraperitoneally injected to every rat and Morris water maze test and shuttle dark avoidance test were carried out respectively to explore the changes of learning and memory capacities in the rats. Besides, after the cerebral cortical neurons of newborn SD rats aged within 3 days were cultured in vitro for 7 days, drug serum containing YZC was added to the cultured neurons before or after beta amyloid peptide(25 - 35) (Abeta(25 - 35)) intoxication to observe the protective effect of YZC on neurotoxicity by MTT assay and to determine the LDH content in the supernatant.</p><p><b>RESULTS</b>Compared with those untreated with YZC, the rats having received YZC treatment got superiority in shorter time of platform seeking in Morris water maze test, as well as elongated latent period and less times of error in shuttle dark avoidance test. On the cultured neurons, YZC drug serum could effectively increase the survival rate of Abeta(25 - 35) intoxicated neurons and reduce the LDH contents in cultured supernatant.</p><p><b>CONCLUSION</b>YZC has an action of improving learning and memory disorder, and good protective effect on Abeta(25 - 35) induced neurotoxicity in SD rats.</p>