Constitutively Active Glycogen Synthase Kinase-3b Gene Transfer Sustains Apoptosis, Inhibits Proliferation of Vascular Smooth Muscle Cells, and Reduces Neointima Formation After Balloon Injury in Rats

Objective—Glycogen synthase kinase (GSK)-3b is a crucial factor in many cellular signaling pathways and may play an important role in smooth muscle proliferation and apoptosis after angioplasty. Methods and Results—To investigate the effect of GSK-3b modulation on neointima formation, smooth muscle proliferation, and apoptosis after balloon injury in vivo, we delivered adenoviral vectors expressing the constitutively active form of GSK-3b (GSK-S9A: 9th serine switched to alanine) or a control gene into rat carotid arterial segments after balloon injury with a 2F Fogarty catheter. Viral infusion mixtures (5310 pfu) were incubated in the arterial lumen for 20 minutes, and the effects of gene delivery were evaluated 3 days and 2 weeks after gene delivery with morphometry and immunohistochemical staining for proliferating and apoptotic cells. There were no significant differences in intimal, medial, and lumen areas at 3 days after the procedure. However, 2 weeks after gene delivery, the active GSK-3b gene transfer resulted in a significantly lower intima to media ratio (0.2960.06 versus 0.8660.09, P,0.01) and a greater lumen area (0.4160.02 versus 0.3160.01 mm, P,0.01) compared with the control gene transfected group. This was attributable to a significant reduction in intimal area (0.0560.01 versus 0.1560.02 mm, P,0.01), whereas the medial area was similar (0.1760.01 versus 0.1860.01 mm, P50.21). Proliferation index was significantly reduced both at 3 days and 2 weeks in the active GSK-3b gene transferred group (2.9760.29% versus 5.7160.50%, P,0.01). In addition, apoptotic index, which was not significantly different between the 2 groups at 3 days, was significantly higher in the active GSK-3b gene transferred group at 2 weeks (3.1460.68% versus 22.761.63%, n510, P,0.01, for control versus active GSK-3b gene transfer). Conclusions—In vivo delivery of the active GSK-3b gene inhibits smooth muscle proliferation, sustains apoptosis, and reduces neointima formation after balloon injury in rats and may be a future therapeutic target to limit neointima hyperplasia after angioplasty. (Arterioscler Thromb Vasc Biol. 2003;23:●●●-●●●.)