CAJ | 학술논문

目的观察血浆游离脂肪酸(FFA)水平升高对大鼠β细胞胰岛素分泌功能的影响,探讨高游离脂肪酸导致β细胞胰岛素抵抗的机制.方法将8周龄雄性SD大鼠按数字随机表法分为脂肪乳输注组(FFA组,15只)和生理盐水输注组(NS组,15只).分别输注72 h,检测以下指标:(1)采血检测胰岛素,FFA水平.(2)正常血糖高胰岛素钳夹实验,评价外周组织胰岛素抵抗程度.(3)静脉葡萄糖耐量实验,评价活体胰岛β细胞分泌功能.(4)胰岛细胞表面灌注实验,评价离体胰岛β细胞动态分泌功能.(5)测定胰腺组织丙二醛(MDA)及还原性谷胱甘肽(GSH)水平.(6)实时荧光定量PCR方法检测胰岛细胞胰岛素受体底物-1(IRS-1)、胰岛素受体底物-2(IRS-2)和葡萄糖转运子-2(Glut-2) mRNA表达的变化.结果 (1)FFA组血中胰岛素水平低于NS组[(12.34±0.98) mIU/L vs(18.12 ±1.28)mIU/L,P＜0.01],FFA水平显著高于NS组[(1.56±0.21) mmol/Lvs (0.65±0.12)mmol/L,P＜0.01]；(2)FFA刺激72 h后,离体和活体的胰岛β细胞分泌功能均降低；(3)FFA组葡萄糖输注率(GIR)较明显低于NS组(P＜0.01),提示存在明显的外周胰岛素抵抗；(4)FFA组胰腺组织MDA水平高于NS组,两组胰腺MDA水平分别为[(1.62 ±0.18) mmol/mg prot vs(0.76 ±0.15)mmol/mg prot,P＜0.01].FFA组胰腺组织GSH水平低于NS组,两组胰腺GSH水平分别为[(22.54 ±2.66) mg/g prot vs (36.58±3.02) mg/g prot,P＜0.01]；(5)FFA组胰岛细胞IRS-1 mRNA表达降低[(36.8±1.8)％,P ＜0.01],IRS-2及Glut-2分别降低[(29.6±1.2)％、(58.7±2.1)％,P＜0.01].结论血浆FFA水平长期升高,造成外周胰岛素抵抗的同时,对β细胞胰岛素分泌有抑制作用,此时胰岛细胞胰岛素信号通路分子基因表达降低.
목적 관찰혈장유리지방산(FFA)수평승고대대서β세포이도소분비공능적영향,탐토고유리지방산도치β세포이도소저항적궤제.방법 장8주령웅성SD대서안수자수궤표법분위지방유수주조(FFA조,15지)화생리염수수주조(NS조,15지).분별수주72 h,검측이하지표:(1)채혈검측이도소,FFA수평.(2)정상혈당고이도소겸협실험,평개외주조직이도소저항정도.(3)정맥포도당내량실험,평개활체이도β세포분비공능.(4)이도세포표면관주실험,평개리체이도β세포동태분비공능.(5)측정이선조직병이철(MDA)급환원성곡광감태(GSH)수평.(6)실시형광정량PCR방법검측이도세포이도소수체저물-1(IRS-1)、이도소수체저물-2(IRS-2)화포도당전운자-2(Glut-2) mRNA표체적변화.결과 (1)FFA조혈중이도소수평저우NS조[(12.34±0.98) mIU/L vs(18.12 ±1.28)mIU/L,P＜0.01],FFA수평현저고우NS조[(1.56±0.21) mmol/Lvs (0.65±0.12)mmol/L,P＜0.01]；(2)FFA자격72 h후,리체화활체적이도β세포분비공능균강저；(3)FFA조포도당수주솔(GIR)교명현저우NS조(P＜0.01),제시존재명현적외주이도소저항；(4)FFA조이선조직MDA수평고우NS조,량조이선MDA수평분별위[(1.62 ±0.18) mmol/mg prot vs(0.76 ±0.15)mmol/mg prot,P＜0.01].FFA조이선조직GSH수평저우NS조,량조이선GSH수평분별위[(22.54 ±2.66) mg/g prot vs (36.58±3.02) mg/g prot,P＜0.01]；(5)FFA조이도세포IRS-1 mRNA표체강저[(36.8±1.8)％,P ＜0.01],IRS-2급Glut-2분별강저[(29.6±1.2)％、(58.7±2.1)％,P＜0.01].결론 혈장FFA수평장기승고,조성외주이도소저항적동시,대β세포이도소분비유억제작용,차시이도세포이도소신호통로분자기인표체강저.
Objective To study the changes and mechanism of the function of islet βcells and insulin signal transduction molecules in rats after long-term period lipid infusion.Methods Thirty SpragueDawley (SD) rats were randomly divided into free fatty acid (FFA) and normal saline (NS) groups.Catheters were implanted under pentobarbital anesthesia in the right atrium via the jugular vein and the left carotid artery.A technique for a 72-h infusion in unrestrained rats was used for triglyceride and heparin or saline infusion.The infusion period was started on day 2 after surgery.After 72-h infusion,fasting serum insulin (Ins) and FFA in the blood were determined.The glucose infusion rat (GIR) was measured by hyperinsulinemia euglycemic clamp to evaluate the peripheral insulin resistance.The intravenous glucose tolerance test (ivgtt) and islet cell perifusion was conducted to evaluate the function of islet β-cell.The rats in two groups were sacrificed,and the pancreatic islets were isolated and collected.The levels of malondialdehyde (MDA) and reduced glutathione hormone (GSH) were detected in pancreatic tissues.The expressions of insulin receptor substrate-1 (IRS-1),insulin receptor substrate-2 (IRS-2),and glucose transporter-2 (Glut2)gene in islets were detected by real-time polymerase chain reaction (PCR).Results (1)The serum FFA concentration in the FFA group was higher than in NS group [(1.56 ± 0.21) mmol/L vs (0.65 ± 0.12)mmol/L,P ＜0.01].(2)The GIR was decreased significantly in FFA group compared with NS group(P ＜0.01).(3)The glucose that stimulated insulin secretion was decreased in the FFA group.(4)The levels of MDA were significantly higher in FFA group [(1.62 ± O.18) mmol/mg prot vs (0.76 ± 0.15) mmol/mg prot,P ＜0.01].The levels of GSH were lower in FFA group [(22.54 ±2.66) mg/g prot vs (36.58 ± 3.02) mg/g prot,P ＜ 0.01].(5) The gene cxprcssion of IRS-1 in islets was significantly decreased by [(36.8±1.8)％,P ＜0.01],and the expression of IRS-2 and Glut-2 was decreased by [(29.6±1.2) ％] and [(58.7 ± 2.1) ％] in FFA group,respectively(all P ＜0.01).Conclusions Lipid infusion in long time decreased the secretion of insulin and impaired the expression of insulin signal transduction molecules in islet βcells.