Abstract: AIM: To observe the protective effect of procyanidins on the aortal injury in rats induced by D-galactose combined with aluminum trichloride and explore its conceivable mechanisms. METHODS: The model of aortal injury rats were established by D-galactose(180 mg·kg^-1·d^-1,i.p.)combined with aluminum chloride(15 mg·kg^-1·d^-1,i.g.). 12 weeks later, aortal injury rats(40) were randomized into blank control group (NS i.p., NS i.g.), aortal injury group (D-gal i.p.+ AlCl₃ i.g.), procyanidins with low and high dosages (PC 20,40 mg/kg; D-gal i.p.+ AlCl₃ i.g.), vitamin E group (VitE 10 mg/kg; D-gal i.p.+ AlCl₃ i.g.) (n=8 for each group). The animals were intragastrically administrated with procyanidins once a day for consecutive 8 weeks.After the last administration, blood pressure was measured by tail cuff. The thoracic aortic ring of rats was mounted on a bath system, and the relaxation induced by acetylcholine was measured. The primary pathologic changes of aorta were observed by HE staining. T-AOC,H₂O₂ and NO in serum were measured by colorimetric analysis. The expression of eNOS protein were measured by immunohistochemistry. RESULTS: With the increase dose of procyanidins, the blood pressure was gradually decreased, the aortic endothelium-derived diastolic function had been improved,the aortal pathological damage had been improved. The levels of serum T-AOC and NO were gradually increased while the level of serum H₂O₂ was gradually decreased. The expression of eNOS protein upregulated inch by inch. CONCLUSION: Procyanidins can significantly decrease the blood preasure,improve the aortic endothelium-derived diastolic function, ameliorate the aortal injury,suggesting this medicine may protect the aorta from injury through increasing the level of serum NO and the expression of eNOS protein expression.

Key words: procyanidins, T-AOC, H₂O₂, NO, eNOS