BACKGROUND:The blood-brain barrier is an important structure that protects the central nervous system,and the study of the effects of high glucose on the blood-brain barrier is important for the prevention of high glucose-induced damage to the central nervous system.OBJECTIVE:To investigate the potential effect of high glucose on the blood-brain barrier function of hCMEC/D3 human brain microvascular endothelial cells.METHODS:hCMEC/D3 cells were cultured in regular sugar medium(glucose concentration of 25 mmol/L)and high-sugar medium(glucose concentration of 55 mmol/L).The morphology of cells in each group was observed by light microscopy.CCK-8 assay was used to detect changes in cell viability.A monolayer blood-brain barrier model was established using hCMEC/D3 cell line with Transwell chamber device.Changes in cell transmembrane resistance were monitored daily.The permeability of cell monolayers was detected by phenol red permeability.Flow cytometry was used to detect the apoptosis rate of the cells.Western blot assay was used to detect the expression of Bcl-2,Bax,Caspase-3,ZO-1,Occludin,Claudin-1,and histone deacetylase 4.The levels of histone deacetylase in cell supernatant were detected by ELISA.The expression of histone deacetylase 4 in cells was detected by immunofluorescence.RESULTS AND CONCLUSION:(1)The cell viability of high sugar group was significantly lower than that of control group(P＜0.000 1).(2)The cells of the control group were in a good growth state,interwoven into a dense mesh,with interconnections between synapses.The cell growth of high glucose group was suppressed,and the connection of inter-cellular synapses was reduced.(3)Compared with the control group,the transmembrane resistance value of the high glucose group was reduced(P＜0.05);phenol-red permeability of the monolayer cell membrane was increased(P＜0.05);cell apoptosis rate was increased(P＜0.01);the expression of Bax protein was increased(P＜0.000 1);the expression of Caspase-3 protein had no significant change(P＞0.05);the expression of Bcl-2,ZO-1,Occludin,Claudin-1,and histone deacetylase 4 proteins was decreased(P＜0.01,P＜0.001,P＜0.01,P＜0.000 1,P＜0.01);the fluorescence expression of histone deacetylase 4 was decreased(P＜0.001)in the high glucose group.(4)The level of histone deacetylase 4 in the cell supernatant of the high glucose group was lower than that of the control group(P＜0.05).The results show that high glucose induces the increased apoptosis and enhances permeability of hCEMCE/D3 cells,and its mechanism may be related to the decreased expression level of histone deacetylase 4.

BACKGROUND:The blood-brain barrier is an important structure that protects the central nervous system,and the study of the effects of high glucose on the blood-brain barrier is important for the prevention of high glucose-induced damage to the central nervous system.OBJECTIVE:To investigate the potential effect of high glucose on the blood-brain barrier function of hCMEC/D3 human brain microvascular endothelial cells.METHODS:hCMEC/D3 cells were cultured in regular sugar medium(glucose concentration of 25 mmol/L)and high-sugar medium(glucose concentration of 55 mmol/L).The morphology of cells in each group was observed by light microscopy.CCK-8 assay was used to detect changes in cell viability.A monolayer blood-brain barrier model was established using hCMEC/D3 cell line with Transwell chamber device.Changes in cell transmembrane resistance were monitored daily.The permeability of cell monolayers was detected by phenol red permeability.Flow cytometry was used to detect the apoptosis rate of the cells.Western blot assay was used to detect the expression of Bcl-2,Bax,Caspase-3,ZO-1,Occludin,Claudin-1,and histone deacetylase 4.The levels of histone deacetylase in cell supernatant were detected by ELISA.The expression of histone deacetylase 4 in cells was detected by immunofluorescence.RESULTS AND CONCLUSION:(1)The cell viability of high sugar group was significantly lower than that of control group(P＜0.000 1).(2)The cells of the control group were in a good growth state,interwoven into a dense mesh,with interconnections between synapses.The cell growth of high glucose group was suppressed,and the connection of inter-cellular synapses was reduced.(3)Compared with the control group,the transmembrane resistance value of the high glucose group was reduced(P＜0.05);phenol-red permeability of the monolayer cell membrane was increased(P＜0.05);cell apoptosis rate was increased(P＜0.01);the expression of Bax protein was increased(P＜0.000 1);the expression of Caspase-3 protein had no significant change(P＞0.05);the expression of Bcl-2,ZO-1,Occludin,Claudin-1,and histone deacetylase 4 proteins was decreased(P＜0.01,P＜0.001,P＜0.01,P＜0.000 1,P＜0.01);the fluorescence expression of histone deacetylase 4 was decreased(P＜0.001)in the high glucose group.(4)The level of histone deacetylase 4 in the cell supernatant of the high glucose group was lower than that of the control group(P＜0.05).The results show that high glucose induces the increased apoptosis and enhances permeability of hCEMCE/D3 cells,and its mechanism may be related to the decreased expression level of histone deacetylase 4.

Objective To construct an in vitro"metabolic memory"cell model of HT-22 mouse hippocampal neurons induced by high glucose,and to investigate the effect of"metabolic memory"on apoptosis and histone acetylation in HT-22 cells.Methods HT-22 cells were cultured in high glucose medium(glucose concentration was 55 mmol/L)and conventional glucose medium(glucose concentration was 25 mmol/L),and cells were divided into the control group(NG 4,6 and 8 groups,25 mmol/L glucose was cultured for 4,6 and 8 days,respectively),the high glucose group(HG 4,6 and 8 groups,respectively)and the metabolic memory group(HG2NG2,HG2NG4,HG2NG6,HG4NG2 and HG4NG4 groups,high glucose culture for 2 days to 25 mmol/L glucose culture for 2,4 or 6 days,high glucose culture for 4 days to 25 mmol/L glucose culture for 2 or 4 days).Cell viability was detected by CCK-8 method.The release of lactate dehydrogenase(LDH)in cell culture supernatant was detected,and the optimal time to establish a"metabolic memory"model was selected.Subsequently,cells were divided into the NG4 group,the NG8 group,the HG4 group,the HG4NG4 group and the HG8 group,and the cell morphology of each group was observed by optical microscope.The apoptosis rate was detected by flow cytometry.The activities of deacetylase(HDAC)and histone acetyltransferase(HAT)were detected by enzyme-linked immunosorbent assay(ELISA).Western blot assay was used to detect expression levels of histone deacetylase 4(HDAC4),B lymphocyte tumor 2(Bcl-2),Bcl-2 related X protein(Bax)and Caspase-3 protein.Results The HG4NG4 group was the ideal cell model with high glucose metabolic memory.Cells of the NG4 group and the NG8 group were interwoven into a dense network,growing well,with spindle shaped cells and distinct synaptic structures.However,in the HG4 group and the HG8 group,the cell body became round,synaptic structure disappeared and growth was inhibited.In the HG4NG4 group,the number of cells increased but their morphology was damaged.Results of flow cytometry showed that compared with the NG8 group,the apoptosis rates were significantly increased in the HG8 group and the HG4NG4 group(P＜0.05).ELISA results showed that compared with the NG8 group,the expression levels of HDAC4,Bax,and Caspase-3 proteins increased in the HG8 group and the HG4NG4 group,while the expression level of Bcl-2 protein significantly decreased(P＜0.05).Compared with the HG8 group,there were no significant differences in protein expression levels of HAT and HDAC in the HG4NG4 group.Western blot reslts showed that compared with the NG8 group,the levels of HDAC4,Bax and Caspase-3 protein increased in the HG8 group and the HG4NG4 group(P＜0.05).Compared with the HG8 group,there were no significant differences in protein expression levels in the HG4NG4 group.Conclusion HT-22 mouse hippocampal neurons cultured with 55mmol/L high glucose for 4 days,and then cultured with 25 mmol/L glucose for 4 days are the ideal"metabolic memory"cell model.The mechanism may be related to the increased activity of HDAC,HAT and HDAC4 expression in the hyperglycemic model.

Objective To explore and validate the mechanism of Prepared Radix Polygoni Multiflori in the treatment of NAFLD based on network pharmacology and animal non-alcoholic fatty liver disease(NAFLD)model experiments.Methods Consult the literature to compare the differences between Radix Polygoni Multiflori and Prepared Radix Polygoni Multiflori(PRPM).Herb database and SwissADME database were used to screen the active ingredients of Prepared Radix Polygoni Multiflori,SwissTargetPrediction database was used to predict its targets,OMIM,DISGENET and GEENCARDS databases were used to screen the NAFLD-related targets,conduct GO functional enrichment analysis and KEGG pathway enrichment analysis.The active ingredient-target-KEGG signaling pathway-NAFLD network was mapped later.The mice with NAFLD were treated with Prepared Radix Polygoni Multiflori by gavage for 8 weeks;serum triglyceride level and alanine aminotransferase(ALT)activity were measured;the liver lesions were observed by HE staining;the potential mechanism of action of Radix Polygoni Multiflori in the treatment of NAFLD was verified by Western blot.Results The differences between Radix Polygoni Multiflori and PRPM were consulted.Six pharmacological components and 32 potential action targets of Radix Polygoni Multiflori for the treatment of NAFLD were screened by network pharmacology,GO and KEGG pathways were enriched to lipid and atherosclerosis-related pathways,AMPK signaling pathway,etc.;HE staining verified that Prepared Radix Polygoni Multiflori has the function of improving NAFLD and is associated with the alteration of FASN,ACC,SCD protein of AMPK signaling pathway.Conclusion Radix Polygoni Multiflori has the potential to improve NAFLD by regulating FASN,ACC and SCD.