AngⅡ Effects On Rat Islet Beta Cells By Oxidative Stress Pathway

Objective:First explore the impact of islet β-cells for different concentrations of angiotensin Ⅱ and different time;Further study the relationship between angiotensin Ⅱ and rat pancreatic β cell apoptosis, And angiotensin Ⅱ receptor blockers is whether has a protective effect on pancreatic islet cells.MethodsRIN-m cells cultured in vitro environment is randomly divided into five groups:(1) Normal control group(Medium without Ang Ⅱ);(2) Ang Ⅱ0.1μmol·L-1group;(3) Ang Ⅱ1.0μmol·L-1group;(4) Ang Ⅱ10.0μmol·L-1group;(5) Zero group. Each group were cultured24h,48h,72h, detect the proliferative activity of islet cells in different concentrations of Ang Ⅱ and different time by MTT colorimetric assay. RIN-m cells cultured in vitro environment is randomly divided into three groups:(1) Normal control group(Medium without Ang Ⅱ);(2) Ang Ⅱ10.0μmol·L-1group;(3) The Ang Ⅱ inhibitor (Losartan) pretreatment group, the cells were cultured72h and collected, Measured cell apoptosis by flow cytometry,; determined ROS of intracellular by Reactive oxygen detection kit; determined the NF-KBp65mRNA expression levels by real-time-PCR; determined the NF-KBp65and p-P38MAPK protein expression levels by western-blot.Result1. Comparison of the proliferation rate of different concentrations of Ang Ⅱ and different time:At the same time, islet cell proliferation rate is decreased with increasing concentration of Ang Ⅱ(P<0.5); The same concentration, islet β cell proliferation rate decreased with increasing time(P<0.5).2. The relation is between Ang Ⅱ and islet cell apoptosis:Compared with the normal group, the apoptosis rate and ROS of Ang Ⅱ is increased(P<0.5); Compared with Ang Ⅱ group, the apoptosis rate and ROS of Ang Ⅱ inhibitor pretreatment group is reduced(P<0.5).3. The mechanism of Ang Ⅱ induced islet cell apoptosis:compared with the normal group, The expression of NF-KBp65mRNA and NF-KBp65, p-P38MAPK protein of Ang Ⅱ group is increased(P<0.5); Compared with Ang Ⅱ group, he expression of NF-KBp65mRNA and NF-KBp65, p-P38MAPK protein of Ang Ⅱ inhibitor pretreatment group is reduced(P<0.5).Conclusions1. Isletβcell proliferation rate decreased with increasing concentration of Ang Ⅱ and time.2. Ang II activate NF-KB/p-P38MAPK pathway by inducing the expression of ROS in pancreatic β cells, promote islet β-cell apoptosis.3. Angiotensin Ⅱ receptor blocking agent has a protective effect on islet cells.