| Alzheimer’s disease is a neurodegenerative diease which closely associated with oxidative stress and threated the quality of life in the eldery.Panax notoginseng saponins is the main active ingredient in Chinese traditional medic ine notoginseng.Previous experimental studies have confirmed that PNS has strong anti free radicals and oxidation and can reduce the level of oxidative stress in AD rats.However,the mechanism of PNS signaling network through oxidative stress and AD treatment is still unc lear.Objective: The subject animal model is the rapid aging dementia model of SAMP8 mice.To observe the effect of PNS on the oxidative stress Nrf2/HO-1 signaling pathway,JAK2/STAT3 signaling pathway in the brain of SAMP8 mice and to identify the location and link of PNS.To discuss the possible mechanism of action.To clarify the mechanism of reducing the level of oxidative stress and to provide more scientific basis for the research and development of the treatment of senile dementia.Methods: SAMP8 mice were randomly divided into model group,the PNS high-dose group(200 mg·kg-1),the PNS low-dose group(100 mg·kg-1),huperzine A group(0.03 mg·kg-1)and the negative control group(SAMR1),15 mice in each group.PNS groups and huperzine A group were deployment with double distilled water gavage administration,negative control group and the model group were given the same volume of distilled water.Irrigation to 1 times a day for 8 weeks.Give medicine after the vis ible spectrophotometric detection of brain tissue of mice in total superoxide dismutase(T-SOD),glutathione peroxidase(GSH-PX)and catalase(CAT)activity;enzyme linked immunosorbent assay in mice brain tissue 8-hydroxydeoxyguanosine(8-OHd G)content of hippocampus neurons were observed;the brain tissues of mice by HE staining;the expression level detected by real-time fluorescence quantitative PCR in mouse brain gene Nrf2,HO-1,JAK2,STAT3mRNA;immunohistochemistry positive cell percentage in mouse brain Nrf2,HO-1,JAK2,SATA3,p-STAT3;the expression level of Western blot method for detection of mouse brain Nrf2 HO-1,JAK2,SATA3,p-JAK2,and p-STAT3 protein.Results: 1.Enzyme activity assay results showed that: compared with the negative control group,model group mice brain T-SOD,GSH-Px and CAT activity decreased significantly(P<0.05);compared with the model group,PNS high,low dose group and stone huperzine divis ion of mouse brain SOD and CAT activity increased significantly(P<0.05 or P<0.01),PNS group mice brain activity of GSH-PX significantly increased(P<0.01).2.Enzyme linked immunosorbent assay showed that compared with the negative group the content of 8-OHd G in the model group was significantly higher(P<0.05).Compared with the model group,PNS groups and huperzine A in mice brain 8-OHd G content decreased significantly(P<0.01).3.HE staining was observed in neuronal cell size of the negative control group was unified,neurons arranged closely,uniform distribution,normal structure.While neurons in hippocampus of model group decreased,the gap bigger,loosely arranged and smaller.Recovery of PNS treatment group and huperzine a group of hippocampus neurons in varying degrees.4.Effect of real-time fluorescence quantitative PCR,immunohistochemistry and Western blot detection PNS on oxidative stress signaling pathway of Nrf2/HO-1 related factor Nrf2 and HO-1: compared with the negative group the model group of Nrf2 and HO-1 protein expression level decreased significantly(P<0.05 or P<0.01),after the intervention of PNS,the PNS groups can up-regulated the expression of Nrf2 mRNA level and Nrf2 immunoreactive cells number(P<0.01);high dose group of PNS can upregulate Nrf2 expression level(P<0.01);high dose group of PNS can be upregulation of HO-1 immunoreactive cell number and protein expression levels(P<0.01).5.Effect of real-time fluorescence quantitative PCR,immunohistochemistry and Western blot detection PNS on oxidative stress signaling pathway of JAK2/STAT3 signaling pathway of oxidative stress related factors JAK2 and STAT3: compared with the negative group,the expression level of STAT3 in the model group mRNA increased significantly(P<0.01),the number of immunoreactive cells of JAK2,STAT3 and p-STAT3 increased significantly(P<0.05 or P<0.01).The increase of protein expression of p-JAK2,STAT3 and p-STAT3(P<0.05 or P<0.01);after the intervention of PNS,PNS JAK2 positive cells in high dose group decreased significantly(P<0.05),elevated total JAK2 protein levels of PNS low dose real time fluorescence quantitative PCR,immunohistochemistry and Western blot detection of PNS on JAK2/STAT3 signaling pathway of oxidative stress related factors JAK2 and STAT3: compared with the negative group,the expression level of STAT3 in the model group mRNA increased significantly(P<0.01),the number of immunoreactive cells of JAK2,STAT3 and p-STAT3 increased significantly(P<0.05 or P<0.01).The increase of protein expression of p-JAK2,STAT3 and p-STAT3(P<0.05 or P<0.01);PNS intervention,PNS JAK2 positive cells in high dose group decreased significantly(P<0.05),elevated total JAK2 protein levels of PNS low dose group(P<0.01),but p-JAK2 protein levels were significantly lower(P<0.05),high dose of PNS the total JAK2 and protein levels of p-JAK2 were significantly lower(P<0.05 or P<0.01);in addition,the PNS high dose group can decrease STAT3 mRNA level(P<0.05),the total percentage of STAT3 positive cells and PNS protein in high and low dosage groups levels were significantly elevated(P<0.01),but the percentage of p-STAT3 positive cells and the protein level of PNS high dose group were significantly decreased(P<0.01).Levels were significantly elevated(P<0.01),but the percentage of p-STAT3 positive cells and the protein level of PNS high dose group were significantly decreased(P<0.01).Conclusion(s):1.PNS can improve the expression level of T-SOD,GSH-PX and CAT in mouse brain and reduce the expression of DNA damage marker 8-OHd G,and ultimately reduce the damage degree of oxidative stress.2.PNS can up-regulate the expression of Nrf2 protein in order to up-regulate the expression of HO-1 protein,and protect the cell from oxidative stress damage.3.PNS can reduce the expression level of p-JAK2 and p-STAT3 by reducing the JAK2 and STAT3,so as to avoid the apoptosis and the effect of oxidative stress. |
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