Effect of salidroside on learning and memory ability of vascular dementia rats

Abstract

INTRODUCTIONIn the western world, vascular dementia (VaD) is the second most common form of adult-onset dementia after Alzheimer's disease (AD). It has an overall prevalence of 1.2 to 4.2% in people aged 65 years or older, and accounts for 10 to 50% of dementia cases, depending on the diagnostic criteria and study population (Knopman et al., 2003). In terms of symptomatology, VaD is characterized by progressive cognition decline, functional ability impairment and behavioral problems. VaD results mainly from ischemic injury or oligaemia to brain areas involved in cognition, memory and behaviour (Román, 2003).Rhodiola crenulata (Crassulaceae, Hongjingtian in Chinese) has been known as a medicinal plant for a long time. This precious perennial herbaceous plant distributed at high altitudes in the Polar Arctic and Alpine regions throughout Europe and Asia (Qu et al., 2009). It was reported that R. crenulata has multiple pharmacological *Corresponding author. E-mail: teng450052@126.com. activities such as, antioxidant (Panossian et al., 2010), antihypoxia (Ming, 1986, antifatigue (Shevtsov et al., 2003), antiapoptosis (Jung et al., 2002), anticancer (Kwon et al., 2008 and enhancement in learning and memory (Petkov et al., 1986). Recently, it was reported that the extract of R. crenulata could improve memory and behaviour of VaD rats and some mechanisms were also investigated (Chen et al., 2008a(Chen et al., , b, 2010Wang and Yang, 2008;Yang et al., 2008). However, the exact neuroprotective constituents in the extract of R. crenulata are still unclear. Salidroside (SD, p-hydroxyphenethyl-b-D-glucoside, C 14 H 20 O 7 , structure is shown in Figure 1) is one of the major active constituents in R. crenulata. It has been reported to possess various pharmacological properties including resisting anoxia, antiaging, anticancer, antiinflammation, antioxidative, antifatigue, antiviral, neuroprotective, hepatoprotective and cardioprotective effects (Diaz Lanza et al., 2001;Laremii and Grigor'eva, 2002;Kanupriya et al., 2005;Kelly, 2001;Kucinskaite et al., 2004;Ma et al., 2009;Nan et al., 2003;Wang et al., 2004Wang et al., , 2009Zhang et al., 2007).According to its neuroprotective activity and high content in R. crenulata, we assumed that SD might have some effects on learning and memory ability of VaD.In the current work, we established rat models of VaD by permanent ligation of bilateral common carotid artery and attempted to investigate the effects of SD on learning and memory ability of VaD rats by Y-maze test.