Studies On The Mechanism Of Cyclocarya Paliurus In The Prevention Of Diabetes

Cyclocarya paliurus has beneficial effects on diabetes therapy because of its hypoglycemic,hypolipidemic and antioxidant properties.However,the potential mechanism has not been fully revealed.In our study,transcriptome study was used to explore the mechanism of Cyclocarya paliurus aqueous extract(CPAE)on diabetes prevention at both gene expression and post-gene expression regulation level,which was based on its pharmacodynamics study.Furthermore,Chinese Medicine Compound Preparation of Cyclocarya paliurus,named Cyclocarya paliurus extractum(CPE),was prepared according to the compatibility law of traditional Chinese medicine theory,of which Cyclocarya paliurus was as the monarch medicine,dendrobium and white mulberry as the subject medicine,and orange peel as the adjuvant medicine.The pharmacodynamic effects on diabetes prevention were determined and its mechanism was further studied by transcriptome study.The main research contents and results were as follows:(1)CPAE intervention significantly reduced fasting blood glucose(FBG),improved glucose tolerance,increased insulin levels in diabetic rats induced by high fat diet and streptozotocin(STZ).The results of biochemical indexes showed that CPAE improved the disorder of blood lipid,decreased oxidative stress damage and inflammatory cytokines levels.The histopathological results showed that CPAE could protect islet cells and reduce lipid accumulation in liver cells.Transcriptome study of pancreatic tissue showed that CPAE up-regulated processes including cell cycle,negative regulation of cell apoptosis and glucose metabolism.In addition,CPAE down-regulated the processes of insulin resistance,chemical carcinogenesis.Results of transcriptome study and RT-PCR showed that CPAE upregulated the mRNA expression of Ddit4,Fgf21,Ins1 and Ins2,which are involved in pancreatic function and survival.Immunofluorescence staining of pancreatic cells indicated that CPAE could promote the proliferation of islet cells.Transcriptome study of liver tissue showed that CPAE down-regulated processes including fatty acid metabolism,metabolism of xenobiotics by cytochrome P450 and chemical carcinogenesis pathway.The regulation network of miRNA-transcription factor(TF)-gene showed that miR-200-3p,miR-375-3p and TF Hes1 were the main nodes of the regulation network,which participated in the regulation of liver lipid metabolism by CPAE.RT-PCR results showed that CPAE downregulated the mRNA expression levels of miR-200a-3p,miR-100-3p,miR-221-5p and miR-375-3p.These results demonstrated that CPAE could prevent diabetes by protecting islets,promoting islet cell proliferation,and improving abnormal metabolism of liver tissue.(2)CPE intervention significantly reduced FBG,improved glucose tolerance,and increased liver glycogen content in the diabetic rats induced by high-fat diet combined with dexamethasone(DXM).Results of pancreatic histopathology and TUNEL detection showed that CPE could protect pancreatic islet and decrease islet cell apoptosis.Meanwhile,CPE increased insulin levels in the serum and pancreatic tissue.H&E staining of liver section showed CPE intervention decreased serious lipid accumulation,which were also verified that CPE decreased total cholesterol(TC),triglyceride(TG)in liver tissue and free fatty acid(FFA)in the serum.Besides,CPE improved oxidative stress state and reduced inflammatory cytokines levels.Transcriptome study of pancreatic tissue disclosed that CPE downregulated the processes related to inflammation and apoptosis.In the regulatory network of miRNAs-TF-genes,TF NF-?B and STAT,and miR-9a/148/200 were the main nodes of the regulatory network involved in inflammation inducing apoptosis process.Results of RT-PCR experiments showed that CPE down-regulated the mRNA expressions of NF-?B/STAT/TNF-a/IL-1?/IL-6/Bax,and up-regualated the mRNA expressions of Ins1/Ins2 and anti-apoptotic gene Bcl2.Transcriptome results of liver tissue showed that CPE up-regulated genes related to fatty acid metabolism,PPAR signaling pathway,liver development and organ regeneration,and down-regulated that related to non-alcoholic fatty liver and gluconeogenesis.In the regulatory network of miRNAs-TF-genes,the TF Srebf1 and Mlxipl,and miR-122/128/192,as the main nodes of the regulatory network,participated in the regulation of lipid metabolism in liver tissue.These results demonstrated that CPE could prevent diabetes through inhibiting inflammatory inducing apoptosis of islet cells,increasing insulin synthesis and secretion,reducing the lipid accumulation of liver tissue,reducing glycoeogenesis and increasing glycogen synthesis.In this study,transcriptome study was conducted to investigate the mechanism of CPAE on preventing diabetes.It was confirmed that CPAE could prevent diabetes by protecting islets,promoting islet cell proliferation,and amending abnormal metabolism of liver tissue.At the same time,Cyclocarya paliurus was used as the monarch medicine to develop CPE,which was demonstrated that CPE could prevent diabetes through inhibiting inflammatory related apoptosis of islet cells,increasing insulin synthesis and secretion,reducing the lipid accumulation of liver tissue,reducing glycoeogenesis and increasing glycogen synthesis.These studies provide important insights into the molecular mechanisms of Cyclocarya paliurus on diabetes prevention and give a demonstration of exploring the mechanism of Chinese herbal medicine on complex diseases.