Effects of tongxinluo on angiogenesis in the carotid adventitia of hyperlipidemic rabbits

Atherosclerosis, as a common arterial disease with high morbidity rate, is reported to be closely associated with adventitia angiogenesis. The present study aimed to investigate the effect of tongxinluo (TXL) on angiogenesis in the carotid adventitia of hyperlipidemic rabbits and the underlying mechanism. A total of 90 experimental rabbits were randomly assigned into the following six groups (n=15 per group): Normal group, model group, low‑dose TXL group, moderate-dose TXL group, high‑dose TXL group and atorvastatin group. The normal group was fed with a standard diet. The model and treatment groups were on a high cholesterol diet for 4 weeks. The serum lipid level of the model group was significantly higher compared with the normal group. TXL serum lipid level compared with the model group. Hematoxylin and eosin, and CD31 staining demonstrated that TXL inhibited adventitia angiogenesis in a dose‑dependent manner. The dihydroethidium probe and fluorescence in situ hybridization results indicated that TXL reduced O2‑ level and positive signal of gp91phox and p22phox mRNA in adventitia. Reverse transcription‑polymerase chain reaction and western blot analysis determined that TXL treatment significantly downregulated the expression levels of the gp91phox, p22phox genes and the vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2) proteins compared with the model group. TXL exhibited a dose‑dependent inhibitory effect on angiogenesis in the carotid adventitia of hyperlipidemic rabbits. This may be associated with the downregulation of reactive oxygen species generation in the adventitia and the suppression of VEGF/VEGFR-2 expression.