Role And Mechanism Of Endothelial Cell Dysfunction Induced By Endoplasmic Reticulum Stress In Bridge Vascular Restenosis After Coronary Artery Bypass Grafting

Part ? The effect of hyperlipidemia(HFD)on endothelial cell dysfunction and neointima formation after arteriovenous grafting in miceOBJECTIVE: Hyperlipidemia increases the formation of neointima after coronary artery bypass grafting,but the mechanism is unclear.This project investigated the effects of hyperlipidemia(HFD)on endothelial cell dysfunction and neointimal formation after arteriovenous grafting in mice.METHODS: Wild-type(WT)C57/B16,male,4-week-old mice on the same genetic background were divided into normal diet group(Control,CTL)and high fat diet group(HFD)with 20 in each group and fed with common diet or 60% high-fat diet for 6months.Their body weight was recorded every week.The arteriovenous graft(AVG)model was established after 6 months before finishing ITT and GTT.At 28 days after AVG,the recipient mice were anesthetized,separating the transplanted arteriovenous vessels and examining it's patency.The transplanted arteriovenous vessels were removed with 10%formalin solution fixed,then took paraffin-embedded sections.Observing the formation of neointimal and the function of endothelial cells in transplanted vessels with HE and immunohistochemical staining.At the same time,extracting RNA samples from transplanted blood vessels for RT-PCR to detect endothelial cell damage markers.Results: 1.Comparing with the normal diet group,HFD significantly increased the body weight and aggravated insulin resistance.2.HE staining and immunohistochemistry showed that HFD significantly increased the neointima formation after AVG;3.HFD significantly increased endothelial cell damage and inflammatory cell infiltration in AVG.Conclusion: HFD increases endothelial cell dysfunction and neointimal formation after AVG.Part ? The role of endoplasmic reticulum stress in endothelial cell dysfunction after AVGOBJECTIVE: Endoplasmic reticulum stress can induce endothelial cell dysfunction.This part investigated the role of endoplasmic reticulum stress in endothelial cell dysfunction after AVG.METHODS: 1.Detecting changes of endoplasmic reticulum stress marker and CHOP in AVG of HFD and control mice;2.Culturing endothelial cells in vitro,treating cells with OX-LDL and endoplasmic reticulum stress protectant,4-PBA and TUDCA,then observing the relationship between endoplasmic reticulum stress and endothelial cell dysfunction;3.Culturing endothelial cells in vitro,knocking down the expression of CHOP protein with sh RNA CHOP firstly,then treating cells with OX-LDL and observing the role of CHOP in endothelial cell dysfunction induced by endoplasmic reticulum stress.Results: 1.HFD significantly increased the expression of endoplasmic reticulum stress marker protein and downstream pathway CHOP in AVG;2.In vitro cell experiments,OX-LDL significantly increased endothelial cell dysfunction,and endoplasmic reticulum stress protective agent can reverse the endothelial cell dysfunction caused by OX-LDL;3.That sh RNA CHOP knockdown CHOP protein expression can protect endothelial cell dysfunction caused by OX-LDL.Conclusion: Endoplasmic reticulum stress is involved in endothelial cell dysfunction after AVG.Part ? The role of CHOP in neointima formation after AVG in HFD conditionOBJECTIVE: To observe the role of CHOP in neointima formation after AVG in HFD condition.METHODS: AVG model was established in CHOP-/-mice and CHOP+/+ mice with common genetic background and the number of mice in each group was 10.At 28 days after AVG,5 mices were given AVG vascular specimens for paraffin-embedded sections,and neointima formation was observed by HE staining.The remaining 5 mices extracted m RNA for RT-PCR to check the VE-cadherin and ICAM-1.Results: 1.CHOP KO reduced neointima formation after AVG in HFD condition;2.CHOP KO reduced endothelial cell injury after AVG.Conclusion: CHOP KO reduces endothelial cell dysfunction caused by HFD and reduces neointimal formation after AVG.