The Effect Of Rosiglitazone On Apoptosis Of Vascular Smooth Musle Cell Of Rat And Mechanism Exploration

Objective To observe the effect of rosiglitazone on apoptosis and expression of Phospho-Smad2/3 and P21^cip1 of thoracic aorta vascular smooth musle cell (VSMC) of rat in vitro .Methods Primary cultures of rat VSMCs were obtained from enzymatically dissociated SD rat thoracic aorta, and experiments were performed using subconfluented cells at passages five through eight. After VSMCs had been serum-starved for 24 hours before they were be used for experiments:1) They were divided into four groups : control group, rosiglitazone(concentration of rosiglitazone was 100umoll in this experiment),rosiglitazone + GW9662, rosiglitazone + anti-TGF-β1, then detected the expression level of p-Smad2/3 after 1 hour and the expression level of P21^cip1after 2 hour by Western-blot.The apoptosis of VSMCs was observed by flow cytometry after 24 hour; 2)They were divided into two groups : control group, rosiglitazone, then detected the expression level of p-Smad2/3 and P21^cip1after 0, 0.5, 1, 2, 6, 12, 24 hour by Western-blot .Result Our studies found that the rate of apoptosis of VSMC treated with rosiglitazone was higher than control group(P〈0.05)after 24 hour..The rate of apoptosis of VSMCs in the groups treated with rosiglitazone + GW9662 or rosiglitazone + anti-TGF-β1 were higher than the group treated with rosiglitazone(P〈0.05),from this we may conclude that GW9662 and anti- TGF-β1 could reverse the apoptosis of VSMC induced by rosiglitazone.The expression levels of p-Smad2/3 in the group treated with rosiglitazone were higher than the control group after 0.5 hour (P〈0.05), and the expression level of p-Smad2/3 reached the highest in 1 hour(P〈0.05)then decreased fast after top(P〈0.05),from this we may conclude that rosiglitazone was able to induce VSMCs expression p-Smad2/3. Furthermore, the levels of p-Smad2/3 in the group treated with rosiglitazone was higher than the groups treated with rosiglitazone + GW9662 or rosiglitazone + anti-TGF-β1, from this we may conclude that the GW9662 and anti-TGF-β1 both could reverse the expression levels of p-Smad2/3 of VSMCs induced by rosiglitazone. The expression levels of P21^cip1 in the group treated with rosiglitazone were higher than the control group after 1 hour(P〈0.05), and the level of P21^cip1 reached the highest in 2 hour(P〈0.05)then decreased slowly after top(P〈0.05),from this we may conclude that rosiglitazone was able to induce VSMCs expression levels of P21^cip1. Furthermore, the levels of P21^cip1 in the group treated with rosiglitazone was higher than the group treated with rosiglitazone + GW9662, from this we may conclude that the expression levels of P21^cip1 of VSMCs induced by rosiglitazone could be reversed by GW9662.Conclusion The apoptotic effect of rosiglitazone in VSMCs could be mediated by a mechanism that includes the activation of PPAR-γ, induced the apoptosis of VSMCs by up-regulation the expression level of the P-Smad2/3 and P21^cip1.