[Effects of Wulongdan on learning and memory abilities of rats with chronic cerebral ischemia].

OBJECTIVE: To evaluate the effect of Wulongdan, a tradition Chinese medicinal preparation, on the learning and memory abilities of rats with chronic cerebral ischemia and explore the mechanisms. METHODS: Male rats with chronic cerebral ischemia induced by permanent ligation of the bilateral carotid arteries were randomized into sham-operated group, chronic cerebral ischemia (model) group, and high-, middle-, and low-dose Wulongdan groups and Yinxingye group. The corresponding treatments were administered in the rats 24 h after the operation once daily for 8 consecutive weeks. Morris water maze and step-through tests were performed after 7 weeks of drug administration. The brain tissues were then taken to observe the morphological changes in the hippocampal neurons with Nissl staining by transmission electron microscopy. RESULTS: Compared with the model group, the latency of finding the platform in Morris water maze test was significantly shortened (P<0.05 or 0.01), and that in step-through test significantly prolonged (P<0.05 or 0.01) in high-, middle-, and low-dose Wulongdan groups and Yinxingye group. In the model group, Nissl staining of the hippocampal CA1 region visualized obvious pathological changes in the neurons, showing a significant difference from the sham-operated and high-dose Wulongdan groups. CONCLUSION: Wulongdan can enhance the learning and memory abilities of rats with chronic cerebral ischemia possibly through a mechanism in relation to neuronal protection in the hippocampus CA1 region.