Protein tyrosine phosphatases (PTPs) are regulators of growth factor signalling in Vascular remodelling. The aim of this study was to evaluate PTP expression in the context of PDGF-signalling in the adventitia after angioplasty. Utilising a rat carotid artery model, the adventitial layers of injured and non-injured vessels were laser microdissected. The mRNA expression of the PDGF beta-receptor, the ligands PDGF-A/B/C/D and the receptor-antagonising PTPs (DEP-1, TC-PTP, SHP-2, PTP1B) Were determined and correlated to vascular morphometrics, proliferation markers and PDGF beta-receptor phosphorylation. The levels of the PDGF beta-receptor, PDGF-C and PDGF-D were upregulated concurrently with the antagonising PTPs DEP-1 and TC-PTP at day 8, and normalised at day 14 after vessel injury. Although the proliferation parameters were time-dependently altered in the adventitial layer, the phosphorylation of the PDGF beta-receptor remained Unchanged. The expression dynamics of specific PTPs indicate a regulatory role of PDGF-signalling also in the adventitia during vascular remodelling. (C) 2009 Elsevier Inc. All rights reserved.