Effect of Danggui Shaoyao San on cognitive function of vascular dementia model rats and its mechanisms / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the effects of Danggui Shaoyao San(DSS) on cognitive function and neuronal apoptosis in vascular dementia (VD) rats.Methods:Fifty SPF grade male SD rats aged 6-7 weeks were randomly divided into sham operation group, model group, positive drug group (nimodipine group, 9.45 mg·kg -1), DSS low-dose group (1.6 g·kg -1), DSS high-dose group (6.4 g·kg -1) according to random number table, with 10 rats in each group. The VD rat model was established by permanent ligation of bilateral common carotid arteries. Seven days after modeling, the rats in different groups were administrated by gavage according to corresponding interventions, once a day, for 28 days. Morris water maze test was used to evaluate the learning and memory ability of rats.The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS) in hippocampal area of rat brain were detected by ELISA.The protein expressions of apoptosis-related proteins Bcl-2, Bax, cleaved Caspase-3 and leptin receptor/glycogen synthase kinase 3β microtubule-associated protein tau(LEP-R/GSK-3β/tau) signaling pathway were detected by Western blot. GraphPad Prism 9 software was used for statistical analysis of data, repeated measure ANOVA and one-way ANOVA were used for comparison between multiple groups, and SNK- q test was used for further pairwise comparison. Results:The results of water maze experiment showed that the time and group interaction of escape latency of the five groups were not significant ( F=1.223, P>0.05), the main effect of group and time were significant ( F=74.65, 18.32, both P<0.05). On the 5th day, the escape latency of nimodipine group, DSS low-dose group and DSS high-dose group were lower than that of model group ( q=14.425, 7.477, 21.392, all P<0.05), and that of DSS high-dose group was lower than that of nimodipine group ((15.28±2.46)s, (22.78±3.31)s, q=6.966, P<0.05). There was statistically significant difference in the number of crossing platforms of rats in 5 groups ( F=17.331, P<0.05). The numbers of platform crossing in nimodipine group and DSS high-dose group were higher than that in model group ( q=6.789, 10.635, 5.270, all P<0.05), and the number of platform crossing in DSS high-dose group was higher than that in nimodipine group ((6.84±1.63), (5.22±1.75), q=3.846, P<0.05). ELISA results showed that the levels of MDA, ROS and SOD in hippocampal tissues of rats in 5 groups were significantly different ( F=49.338, 38.518, 15.440, all P<0.05). The levels of MDA and ROS in hippocampus of DSS high-dose group were lower than those of model group ( q=16.061, 13.541, both P<0.05) and nimodipine group ( q=4.317, 5.162, both P<0.05), SOD level of DSS high-dose group was higher than those of model group ( q=8.179, P<0.05) and nimodipine group ( q=4.135, P<0.05). Western blot results showed that the levels of apoptosis-related proteins Bcl-2/Bax and Caspase-3 were significantly different in the 5 groups ( F=30.692, 43.384, both P<0.01). The level of Bcl-2/Bax in DSS high-dose group was higher than that in model group ( q=10.562, P<0.05) and nimodipine group ( q=3.820, P<0.05), the level of Caspase-3 was lower than those of model group ( q=12.139, P<0.05) and nimodipine group ( q=7.734, P<0.05). The levels of LEP-R, p-GSK-3β, p-S404 tau and p-S202 tau expression level in hippocampal tissues of the 5 group were significantly different ( F=80.927, 59.230, 159.784, 105.923, all P<0.01). The levels of LEP-R and p-GSK-3β protein in nimodpine group and DSS high-dose group were higher than those in model group ( q=16.275, 20.104, both P<0.05; q=12.942, 17.257, both P<0.05), the levels of p-S404 Tau and p-S202 Tau in the two groups were lower than those in model group ( q=19.121, 27.456, both P<0.05; q=17.559, 22.780, both P<0.05). The levels of LEP-R(0.98±0.15), (0.86±0.14)) and p-GSK-3β((0.95±0.16)s, (0.82±0.13)) in DSS high-dose group were higher than those in nimodipine group ( q=3.829, 4.314, both P<0.05), the levels of p-S404 Tau((0.41±0.03)s, (0.58±0.07)) and p-S202 Tau((0.48±0.05)s, (0.59±0.06)) in DSS high-dose group were lower than those of nimodipine group ( q=8.335, 5.220, both P<0.05). Conclusion:DSS can improve the cognitive function of VD rats, and the mechanism may be related with reducing oxidative stress level, inhibiting neuronal apoptosis, and upregulating LEP-R/GSK-3β/Tau signaling pathway.