Pioglitazone induced proliferation of VSMC through PPARγ. A. Proliferation of VSMCs is regulated by pioglitazone through PPARγ signaling pathway. VSMCs alone (control), transduced with Ad-vector, Ad-wt-PPARγ, or siRNA-PPARγ were labeled with BrdU, respectively. In addition, VSMCs treated with pioglitazone (PIO) (1uM), wt-PPARγ-overexpressing VSMCs treated with PIO (Pio + wt-PPARγ), and PPARγ silenced VSMCs treated with PIO (Pio + siRNA) were harvested 24 h later after treatment followed by BrdU labeling. The BrdU positive VSMCs from indicated groups were recorded by confocal microscopy (600x). BrdU positive VSMCs cells from wt-PPARγ, PIO + wt-PPARγ, and PIO alone groups were less than those from control and vector alone groups. On the other hand, the addition of PIO in the absence of PPARγ (PIO + siRNA-PPARγ) and GW6992 alone induced the proliferation of VSMCs. The data is the representative of three individual experiments. B. The ratio of BrdU positive cells to total cells was quantified. The BrdU positive cell numbers and total cell numbers from each field were counted and the ratio of BrdU positive cell versus total cell numbers was calculated. **P < 0.01, *P < 0.05. Each experiment has been repeated three times.