Objective:To analyze the relationship between the social network characteristics and mental health of elderly people in rural areas.Methods:A total of 274 elderly individuals aged 60 and above from rural communi-ties were selected.A self-designed structured interview questionnaire on social network structure was used to collect social network data,and Brief Version of the Mental Health Inventory for the Elderly(MHIE)was used to assess mental health levels.Based on the social escort model,the elderly people's social relationships were represented u-sing a three-tier concentric circle structure,indicating different levels of social relationship closeness.The structure of the social network included the size,frequency of contact,and intimacy of the relationships.The network size was represented by the number of nominators,and heterogeneity refers to the different types of relationships.Results:The concentric circle structure of the social network of rural elderly people consists of core family relationships,ex-tended family relationships,and friendships,from inner to outer circles.Regression analysis results showed that the heterogeneity of the social network was positively correlated with the MHIE scores(β=2.58).The intimacy of ex-tended family members and friends was positively correlated with the MHIE scores(β=1.07,0.87).The size of the extended family members was negatively correlated with the MHIE scores(β=-5.52).Conclusion:The het-erogeneity of the social network and intimacy play a positive role in the mental health of rural elderly people,while a large extended family network may impose psychological burdens.

Objective:To analyze the relationship between the social network characteristics and mental health of elderly people in rural areas.Methods:A total of 274 elderly individuals aged 60 and above from rural communi-ties were selected.A self-designed structured interview questionnaire on social network structure was used to collect social network data,and Brief Version of the Mental Health Inventory for the Elderly(MHIE)was used to assess mental health levels.Based on the social escort model,the elderly people's social relationships were represented u-sing a three-tier concentric circle structure,indicating different levels of social relationship closeness.The structure of the social network included the size,frequency of contact,and intimacy of the relationships.The network size was represented by the number of nominators,and heterogeneity refers to the different types of relationships.Results:The concentric circle structure of the social network of rural elderly people consists of core family relationships,ex-tended family relationships,and friendships,from inner to outer circles.Regression analysis results showed that the heterogeneity of the social network was positively correlated with the MHIE scores(β=2.58).The intimacy of ex-tended family members and friends was positively correlated with the MHIE scores(β=1.07,0.87).The size of the extended family members was negatively correlated with the MHIE scores(β=-5.52).Conclusion:The het-erogeneity of the social network and intimacy play a positive role in the mental health of rural elderly people,while a large extended family network may impose psychological burdens.

Objective To explore the protective effects of dipeptidyl peptidase-4 inhibitor (DPP-4I) on AD-like neurodegenerative changes and its mechanism. Methods The human neuroblastoma cell line SH-SY5Y on the logarithmic phase was divided into six groups:control group (CON group, treated with PBS contained 1‰DMSO for 12 h), wortmannin intervention group (W group, treated with 0.03 μmol/L wortmannin for 12 h), DPP-4I intervention group (DPP-4I group, treated with 10μmol/L DPP-4I for 12 h), both DPP-4I and wortmannin intervention group (DPP-4I+W group, pre-treated with 10 μmol/L DPP-4I for 2 h, then 0.03 μmol/L wortmannin for 12 h), DPP-4I, wortmannin and Ex9-39 intervention group (DPP-4I+W+Ex9-39 group, pre-treated with 10μmol/L Ex9-39 for 2 h, then 10μmol/L DPP-4I for 2 h followed by 0.03μmol/L wortmannin for 12 h), and Ex9-39 intervention group (Ex9-39 group, treated with 10μmol/L Ex9-39 for 12 h). MTT assay was used to detect the cell vitality. Western blot assay was used to detect the level of total tau protein (tau-5) and phosphorylated tau at different sites (pSpS199/202, pT231 and pS396), the level of phosphorylated neurofilaments (NF-H, NF-M) and phosphorylation of critical enzyme in PI3K/Akt/GSK-3β signaling pathway. Results (1) The cell vitality decreased, the levels of pSpS199/202, pT231, pS396 and NF-H/M increased significantly in W group than those in CON group. However, comparing with CON group, the above mentioned parameters reversed in DPP-4I group. Comparing with W group, the cell vitality increased and phosphorylated levels of above mentioned indices were decreased in DPP-4I+W group. (2) The cell vitality showed a decline trend while the levels of phosphorylation tau at three different sites and NF-H/M were higher in Ex9-39 group than those in CON group. Comparing with DPP-4I+W group, the results of the phosphorylated levels showed the same changes in DPP-4I+W+Ex9-39 group. (3) Comparing with CON group, the expression levels of phosphorylated PI3K, Akt and GSK3β increased significantly in DPP-4I group, while those decreased in W group. Additionally, the expression levels of phosphorylated PI3K, Akt and GSK3β were significantly increased in DPP-4I+W group than those in W group. Conclusion DPP-4I can enhance the level of GLP-1 and activate PI3K/Akt/GSK-3βinsulin signaling pathway to improve the hyperphosphorylated tau and NFs induced by wortmannin, and to protect AD-like neurodegeneration.