Study On The Effects Of Ginsenoside Rg₂ On Neuronal Apoptosis In Vascular Dementia Rats Simulated By Cerebral Ischemia Reperfusion

Objective To study the behavior of VD rats which were simulated by the middle cerebral artery occlusion (MCAO)-reperfusion method and the expression of protein BCL-2, BAX, HSP70, P53, which were influenced by ginsenoside Rg2, and to explore the mechanism of ginsenoside Rg2 on VD rats simulated by cerebral ischemia reperfusion (CIR) as well. Vascular dementia (VD) has already become a disease endangering the health and life quality of the aged seriously with the severity of aging population. Therefore, studying the mechanism, preventive and curative measurements has great significance. Many previous researches have shown that ischemic cerebral diseases occupy the important status among the causes of VD. The probability of apoptosis plays an important role in the development and prognosis of VD, which is caused by ischemia reperfusion. Apoptosis is an independent course of cell death which is controlled by genes. The genes can be divided into two categories according to their functions, one is induced genes, the other is inhibitory genes. BCL-2 and HSP70 belong to the former, while BAX and P53 belong to the latter.Methods Ischemia was induced by occluding middle cerebral artery with intraluminal filament for 1 hour, then the circulation was restored for 48 hours. Different dosage of ginsenoside Rg2 was given 15 minutes before reperfusion and 24 hours after reperfusion respectively for therapy, contrasting with nimodipine. To assess the activity of VD rats after operation, measure their memory abilities by model Y maze 48 hours after reperfusion, observe the pathological changes of their cerebral histology and measure the expression of protein BCL-2, BAX, HSP70, P53 with immunohistochemistry method.Results The memory ability of VD rats decreased obviously compared withthe normal and sham groups (P < 0.01). The expression of BCL-2 and HSP70 increased, while BAX and P53 decreased in VD rats. The movement function and memory ability of rats was obviously improved after using ginsenoside Rg2. Compared with the model group, the expression of protein BCL-2 and HSP70 are higher, while the expression of protein BAX and P53 are lower (P < 0.01). Moreover, the curative effect of high dosage (lOmg/Kg) is superior to that of low (2.5mg/Kg) and median (5mg/Kg) dosage. That is to say, the curative effect of ginsenoside Rg2 has dosage dependency.Conclusion The memory ability of vascular dementia rats simulated by cerebral ischemia reperfusion decreased. Neuronal apoptosis happened in CPu area. Furthermore, the expression of apoptosis associated protein BCL-2 and HSP70 decreased, while the expression of protein BAX and P53 increased. Ginsenoside Rg2 can improve the memory ability of VD rats, which is simulated by CIR, inhibit the incidence of apoptosis after CIR by resisting the free radical of oxygen and the influx of calcium. In addition, it can modulate the expression of apoptotic relevant genes.LiuAiling(Physiology) Directed by: Prof JinYi...