Objective To observe the preventive effects of
Tongmaining Capsules (TC) on the restenosis after percutaneous transluminal
angioplasty (PTA) and initially investigate the mechanism of the effects of TC. Methods The rabbit model of the restenosis after PTA was established by carotid balloon injury method. The rabbits were randomly divided into 5 groups (10 animals in each group), namely the sham operation, control, TC large dose, TC middle dose, and TC small dose. The animals in the sham group were only given external carotid artery ligation without balloon injury. After the carotid balloon injury, the animals in the rest 4 groups were intragastrically given 0.5% suspension of sodium carboxymethyl cellulose, 10 ml/kg·d -1; TC, 1.64 g/kg·d -1; TC, 0.82 g/kg·d -1; and TC, 0.41 g/kg·d -1, respectively; and all the doses were given successively for 21 days. 1 Hour after the administration on the 21st day, the animals in each group were executed and their internal carotid arteries were isolated for observing the morphological changes of the carotid artery wall by macroscopical observation and hematoxylin-eosin staining, and for detecting collagen formation of the vascular wall and the expressions of VEGF and bFGF by Masson staining and immunohistochemical techniques, with the help of an image analysis system to make semiquantitative analyses. Results On the 21st day after undergoing PTA, the carotid arteries of the rabbits in the control group showed markedly thickened tunica intima and smooth muscle cell proliferation, rather thickened tunica media and an increase in vascular wall collagen, and increased expressions of VEGF and bFGF as well, as compared with the sham operation group (P<0.01). The large dose of TC (1.64 g/kg·d -1) could markedly reduce the thickness of the tunica intima and tunica media, lessen the collagen in the carotid artery wall, and decrease the expressions of VEGF and bFGF, as compared with the control group (P<0.05, P<0.01), but the values of these criteria were still higher than those found in the sham operation group (P<0.01). The middle and small doses of TC (0.82 g/kg·d -1, 0.41 g/kg·d -1) only slightly affected some of the above-mentioned criteria without significant difference as compared with the control group (P>0.05). Conclusion Large dose of TC exert certain preventive effects on the restenosis after PTA, which may be related to its decreasing the expressions of VEGF and bFGF in the smooth muscle cells of carotid artery wall.