The change in phospholipase C-gamma1 expression following balloon injury to the rat carotid artery

Lim, Seong Hoon; Heo, Young Sun; Kim, Hak Jin; Lee, Wang Soo; Ahn, Ji Hyun; Song, Young Bien; Kim, Sang Wook; Kim, Tae Ho; Kim, Chee Jeong; Ryu, Wang Seong; Ryoo, Un Ho

Abstract

BACKGROUND: While inositol phospholipid-specific phospholipase C (PLC) plays a central role in signal transduction pathways, little is known about its role in the vascular response to injury. Recent studies have shown that phospholipase C-gamma1 (PLC-gamma1) is required for PDGF-induced DNA synthesis and angiotensin II signaling. This study was undertaken to determine the potential involvement of PLC-gamma1 in the in vivo response to vascular injury.
METHODS
Vascular injury was achieved in the left common carotid artery of six-month-old male Wistar rats. The expression of PLC-gamma1 was evaluated at serial time points by immunohistochemistry and Western blot analysis following balloon de-endothelialization of the rat carotid artery.
RESULTS
In the denuded carotid artery at 1 week, the neointima became thicker in a symmetrical manner with respect to the long axis. A strong expression of PLC-gamma1 at one week after injury was seen primarily in the thin layers of neointima. This increased immunoreactivity of PLC-gamma1 persisted at 2-3 weeks after injury, coinciding with the time when neointima gains of its mass. At 4 weeks after injury, staining intensity slightly declined but levels remained elevated. As determined by Western blot analysis, the amount of PLC-gamma1 was about 3-fold higher at 3 weeks after injury compared to uninjured vessels (p<0.01).
CONCLUSION
These results suggest that the amplification of traffic within signal transduction pathways involving PLC-gamma1 occurs and may play a significant role in neointima formation following arterial injury.