Objective: To establish the improved multi-infarct dementia (MID) model

and observe the protective effect and pathway of paeoniflorin on MID model rats. Method: The classic rat's MID model was used to observe protective effect and pathway of different doses of paeoniflorin. The learning and memory abilities of rats were detected by Morris water maze. The expressions of Bcl-2 and Bax protein were detected by immunohistochemical.The changes of cerebral cortex and the neuron structure were detected by HE staining and electron microscopy. Result: The control group had no behavior change. The nerve behavior evaluation

oblique pull test

learning and memory and Brain neurons were affected compared withthe sham-operation group.But the nerve behavior evaluation

oblique pull test

learning and memory and Brain neurons were all significantly improved compared with model group

the expression of Bcl-2 was increased and Bax was restrained. Conclusion: The paeoniflorin has significant improvement effect on the rats' MID model

So its protective mechanism is related with the Bcl-2 and Bax protein expression.