Purpose: Proliferation, migration, and the accumulation of extracellular matrix (ECM) protein of vascular smooth muscle cells (VSMC) play roles for transplant arteriosclerosis. We have previously reported that carvedilol (CA) inhibits the proliferation and the migration of VSMCs. The present study examined the effects of CA on platelet-derived growth factor (PDGF)-induced collagen synthesis in VSMC and the roles of reactive oxygen species (ROS), extracellular signal- regulated protein kinase (ERK), and p38 mitogen-activated protein kinase (p38 MAPK).
Methods: Primary cultured rat VSMCs were obtained from aorta of Sprague-Dawley rats. Growth arrested and synchronized cells were pretreated with CA (10 nM~10microM) at 1 hour before the addition of PDGF 10 ng/ml. Collagen synthesis was measured by 3[H]-proline incorporation, ROS by flow cytometry using ROS-sensitivedichlorofluorescein (DCF) dye, and the activation of ERK andp38 MAPK by Western blot analysis.
Results: PDGF significantly increased collagen synthesis by 2.0-fold, intracellular ROS by 1.6-fold, the activation of ERK 1/2 and p38 MAPK by 4.2-fold and 3.9-fold compared to control, respectively. CA above 1microM inhibited PDGF-induced collagen synthesis. CA also inhibited DCF-sensitive ROS and the activation of ERK and p38 MAPK. All pharmacological inhibitors of ROS, ERK, and p38 MAPK effectively inhibited PDGF-induced collagen synthesis.
Conclusion: These data suggest that CA inhibit PDGF-induced collagen synthesis possibly through inhibiting intracellular ROS and ERK 1/2 and p38 MAPK activation.
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