| Objective: To establish an aging rat model by subcutaneous injection of D-galactose(D-gal),Trillium tschonoskii Maxim(TTM)was used for gavage them.we observe the changes of BDNF-Trkb pathway-related proteins to explore the effect of Trillium tschonoskii Maxim on cognitive ability of aging rats and its possible mechanism.Methods:60 male SD rats were randomly divided into five groups: normal(control group),model(D-gal group),TTM low dose(D-gal+50 mg/kg TTM group),TTM medium dose(D-gal+100 mg/kg TTM group),TTM high dose(D-gal+200 mg/kg TTM group).Except for the control group,the other groups were subcutaneously injected with 100 mg/kg D-gal every day,while the control group was subcutaneously injected with the same dose of saline every day.The TTM groups were given the corresponding concentration of TTM extract every day for 42 consecutive days.Morris water maze was used to detect spatial learning and memory ability of rats;HE staining was used to detect the morphology of hippocampal tissue after perfusion;The expression of 8-hydroxy-2-deoxyguanosine(8-OHDG)in hippocampus was analyzed by immunofluorescence,brain-derived neurotrophic factor(BDNF),tyrosine kinase B(Trkb)and P-Trkb were detected by Western Blot,MDA content was determined by thiobarbituric acid and xanthine was used.The activity of SOD was determined by xanthine oxidase method.Results:1 Test of spatial learning and memory ability in rats(1)The experimental results of water maze navigation showed that: Compared with the control group,the escape latency time of the model group was significantly prolonged(P<0.01),and the action route was disordered and the tendency was poor;Compared with the model group,the escape latency time of the TTM intervention groups was significantly shortened(P <0.05 or P <0.01).(2)Water maze space exploration experiment showed that: Compared with thecontrol group,the target quadrant duration of rats in the model group was significantly shorter(P<0.01),and the number of times of traversing the platform was significantly less(P<0.01);compared with the model group,the time of traversing the platform quadrant of rats in the TTM intervention groups was significantly longer(P<0.05 or P<0.01),and the number of times of traversing the platform was increased(P<0.05 or P<0.01).2 Microscopic observation of hippocampus in rats(1)HE staining results showed that: The number of neurons in the hippocampus of the control group was more,arranged tightly and morphologically intact,the cytoplasm was abundant and the nucleus was plump;the neurons in the model group were scattered and loose,many nuclei were lost,the nucleus morphology was broken,swelling and vacuolation were more,and the number of neurons was significantly less than that in the normal group;compared with the model group,the TTM intervention group was more obvious than that in the model group.The number of nerve cells increased markedly,the arrangement of nerve cells was slightly disordered,and the changes of cell damage were significantly alleviated.The difference was greatest in the middle dose group.(2)Immunofluorescence results showed that: Compared with the control group,the number of 8-OHDG positive neurons in the hippocampus of the model group was significantly increased;Compared with the model group,the number of 8-OHDG positive neurons in the TTM intervention groups was significantly reduced,with the greatest difference in the middle dose.3 Expression of BDNF and its receptor in rat hippocampusWestern Blot results showed that the content of BDNF,Trkb and P-Trkb protein in hippocampus of model group was significantly lower than that of control group(P<0.01),and the difference was statistically significant.Compared with model group,the expression of BDNF,Trkb and P-Trkb protein in TTM low-dose intervention group was significantly higher(P<0.05),and the difference was statistically significant;compared with model group,the expression of BDNF in TTM medium-dose intervention group was significantly higher(P<0.05).The expression ofTrkb and P-Trkb were significantly increased(P<0.05),and the expression of P-Trkb was also significantly increased(P<0.01).Compared with model group,there was no significant difference in BDNF and Trkb between TTM high dose intervention group and TTM high dose intervention group,but the expression of P-Trkb was significantly increased(P<0.05).4 Detection of SOD and MDA in hippocampus of ratsCompared with the control group,SOD activity and MDA content in hippocampus of model group decreased significantly(P<0.001)and increased significantly(P<0.001).Compared with model group,SOD activity and MDA content in hippocampus of TTM low-dose group decreased,but the difference was not significant.Compared with model group,SOD activity in hippocampus of TTM medium-dose group increased significantly(P<0.01),MDA content decreased significantly(P<0.01).Compared with the model group,the activity of SOD in hippocampus of TTM high dose group increased significantly(P<0.05),and the content of MDA decreased significantly(P<0.05).Conclusion: 1 TTM can improve the spatial learning and memory ability of aging rats.TTM can improve the antioxidant capacity of hippocampus in aging rats.TTM can reduce the degeneration of hippocampal neurons and DNA damage in aging rats.TTM can increase the expression of BDNF,Trkb and P-Trkb in hippocampus of aging rats. |
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