Effect Of Angiotens, Captopril And Losartan On The Proliferation And Apoptosis Of Vascular Smooth Muscle Cells

Objective: This study is designed to observe the effect of ACEI captopril and AngII receptor antagonist Iosatan on the proliferation and apotosis of the Vascular smooth muscle cells (VSMCs)in rats which reduced by Ang II, and to explore the role of then in the prevention mechanism of the anti-atherosclerosis and restenosis on the cytological and molecular biological levels.Methods: Male wistar rats were killed and the thoratic aorta was taken out for the primary culture. The proliferation models of vascular smooth muscle cells were estabilished and used for the experiment at passage numbers 5-10. Cultured VSMCs were divided into control group, Ang II group, CP group, LT group, and CP+LT group according to different Ang II concentration and action time. The proliferation and apoptosis ratio of VSMCs and the apoptotic change of the ultramicrostructure of the cultured cells were detected by the methods of MTT, cell number counting, flow cytometry and transmission electron microscope.Results: (1)Compared with the control group, the MTT OD value and cell number counting were increased to 111.88%,108.05% and 246.11%,122.7% after giving AngII24h and 48h recspectively, theses are significant difference (P<0.01). Ang II had no effect on VSMC proliferation at 12 hours (P>0.05), and the proliferation promoting effect was significant decreased at 72 hours (P>0.05).(2)Compared with Ang II group, at the AngII action time of 24h, 48h and 72h, the MTT OD value was decreased to 34.74%, 56.08% and 57.54% (P<0.05) and the cell number counting was decreased to 38.78%, 45.41% and 44.37% (P<0.05) in the CP group. There was a similarity in the LT group(P<0.05). Combination of CP and LT had more remarkable inhibition effect on the proliferation of VSMC.(3)With serun starvation treatment for 72hours, 88.27% of VSMCs located in the G0/G1 phase and 11.73% in the S/G2-M phase. After stimulated by Ang II at the concentration of 10-6 mol/L, 55.87% of VSMCs transmitted into S/G2-M phase. At the Ang II concentration of 10'6 mol/L, the percentage of VSMCs in the S/G2-M phasewere decreased 22.48% in CP group, 25.62% in LT group and 19.87% in CP+LT group respectively. All of these show significant difference(P<0.05)compared with the control group.(4) Compared with the control group, the apoptosis ratio was significant increased 13.64+0.15*(P<0.05) at high concentration 10-4mol/L) of AngII .Compared with AngII group,it was increased to 22.65+ 1.97(P<0.01), 18.80+1.1 l(P<0.05) at the concentration of 10-6, 10-4mol/L in CP group; 17.33 + 2.05, 19.83 + 1.08 (P<0.01) in LT group and 28.46 + 3.31, 27.33+ 3.09(P<0.01).(5)It was observed by transmission electron microscope that the organlli such as mitochondria and endopastic reticula were reduced and the apoptosis body emerged obviously in Applied with CP and LT group.Conclusion: AngII can promote proliferation of VSMCs in a concentration-depending and time-depending style. The action increases when the time is prolonged. Low concentration of Ang II has no significant effect on proliferation of VSMCs. Low and moderate concentration of Ang II has no effect on apoptosis of VSMCs. High concentration of AngII can induce the apoptosis of VSMCs. Captopril or Lasatan has strong inhibition process and apoptosis inducing effect on perliferating VSMCs. Applied with the combination of Caplopril or Lasatan is more remarkable.