Investigation of protective mechanisms of Atorvastatin against high glucose environment-induced injuries of myocardial microvascular endothelial cells / 中华老年医学杂志

ABSTRACT

Objective To investigate the protective mechanisms of Atorvastatin against high glucose environment-induced injuries of myocardial microvascular endothelial cells. Methods Myocardial microvascular endothelial cells(MMECs)in SD rat were cultured and divided into groups of control group ,hyperglycemia group ,atorvastatin group ,and atorvastatin + high glucose group. The level of reactive oxygen species (ROS)was assayed using Superoxide Assay Kit. Apoptosis of cells was detected by terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL) . The expression levels of Akt1 and β1-Integrin were assayed by short-interfering RNA (siRNA ) technique ,and the levels of small GTP-binding protein dissociation stimulator (SmgGDS) expression were measured using Western blot. Results (1)The level of ROS was higher in the high glucose group than in the control group(t=4.154 ,P <0.01) ,and lower in both Atorvastatin group and the Atorvastatin + high glucose group than in the high glucose group (t= 4.233 and 2.893 ,both P <0.05). (2)The proportion of apoptotic cells was higher in the high glucose group than in the control group(t= 4.058 ,P < 0.01) ,and lower in both Atorvastatin group and the Atorvastatin + high glucose group than in the high glucose group(t=4.157 and 2.601 ,both P<0.05).(3)The expression level of Akt1 was lower in the high glucose group and the high glucose + Atorvastatin group than in the mock control group after transfection of Akt1-siRNA(t=4.058 and 4.167 ,both P<0.01).The expression level of β1-integrin was lower in the high glucose group and the high glucose + atorvastatin group than in the mock control group after transfection of β1-integrin-siRNA (t=4.073 and 4.215 , both P<0.01). (4)Western blot analysis showed the following results. First ,the relative expression levels of SmgGDS in both the low dose(1 μmol/L)and high dose(10 μmol/L)of atorvastatin group were higher than in the control group (t= 2.671 and 2.832 ,both P < 0.05).Second ,the relative expression level of SmgGDS in the high dose group were higher than in the low dose group (t=2.612 , P< 0.05 ). Third ,after transfection of Akt1-siRNA ,the expression level of SmgGDS in the high glucose + Atorvastatin group and the high glucose group was decreased ;and the level was higher in the high glucose + atorvastatin + mock group than in the high glucose + mock group(t=4.051 ,P<0.01).Fourth ,after transfection of β1-integrin-siRNA ,the expression level of SmgGDS was lower in high glucose + Atorvastatin group and the high glucose group than in the high glucose +Atorvastatin + mock group ;the level was higher in the high glucose + Atorvastatin + mock group than in the high glucose + mock group(t= 4.068 ,P < 0.01).Fifth ,the expression level of Akt phosphorylation in the high glucose group and the high glucose + Atorvastatin group was higher at 10 minutes than at five minutes(t=2.608 ,P<0.05) ,and higher at 15 minutes than at 10 minutes(t=3.127 ,P <0.05). After transfection of β1-integrin-siRNA ,the expression level of p-Akt /t-Akt was lower in the high glucose group than in the high glucose + mock group(t= 3.371 ,P < 0.05). Conclusions Atorvastatin treatment protects myocardial microvascular endothelial cells possibly by up-regulating SmgGDS through β1-integrin/Akt1 against high glucose environment-induced oxidative stress and apoptosis injuries.