Propylthiouracil modulates aortic vasculopathy in the oxidative stress model of systemic sclerosis.

BACKGROUND: In systemic sclerosis (SSc) vasculopathy affects small arteries and capillaries, but recent evidences show also macrovascular alterations. Experimental data suggest that propylthiouracil (PTU) abrogates the development of cutaneous and pulmonary fibrosis during SSc. The aim of this study was to evaluate the effect of propylthiouracil on aortic lipid peroxidation, intima-media thickness and myofibroblasts differentiation in experimental SSc. METHODS: SSc was induced in BALB/c mice by daily subcutaneous injections of hypochlorous acid (HOCl) for 6weeks. Mice (n=25) were randomized to receive daily: HOCl (n=10), HOCl+PTU (n=10), or vehicle (n=5). Thoracic aorta was evaluated by histological methods to measure intima-media thickness and by immunostaining for α-smooth muscle actin (α-SMA) to assess myofibroblast differentiation. Aortic and plasma levels of malondialdehyde (MDA) were also measured. RESULTS: HOCl induced a significant increase in aortic intima-media thickness compared to controls (p<0.001), while PTU administration prevented intima-media thickening (p<0.01). Myofibroblast differentiation was also less evident in HOCl+PTU-treated animals (p<0.05) compared to mice treated with HOCl alone. The increase in aortic and plasma MDA levels induced by HOCl, was significantly prevented by PTU administration (p<0.05). CONCLUSION: PTU, by reducing lipid peroxidation, prevents aortic thickening and myofibroblast differentiation induced by HOCl, reducing macrovascular alterations in experimental SSc.