Effects of puerarin on expression of cardiac Smad3 and Smad7 mRNA in spontaneously hypertensive rat.

ABSTRACT

AIM OF THE STUDY Puerarin is a pure extract from traditional Chinese medicine Kudzu root. It has been used to treat hypertension and angina pectoris. In our previous study, it showed a protective effect against cardiac hypertrophy in rats. This study was to observe effects of puerarin on expression of cardiac transforming growth factor ß(1) (TGF-ß(1)), Smad3 and Smad7 mRNA in the spontaneously hypertensive rat (SHR), and to explore its possible mechanism of myocardial protection. MATERIALS AND METHODS: Thirty-five 12-week-old SHRs were randomly allocated into 5 groups of 7 rats as follows 3 groups which received intraperitoneal (i.p.) puerarin (100 mg kg(-1), 50 mg kg(-1) and 25 mg kg(-1)), 1 group which received captopril (30 mg kg(-1), i.g.) and 1 control group of untreated SHRs. In addition, a control group of 7 Wistar-Kyoto (WKY) rats was established. Both control groups received i.p. injections of saline. All rats were treated for six weeks. At the end of this period all rats were sacrificed, and their hearts were quickly removed for semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis. RESULTS: Compared with WKY control group, expression of TGF-ß(1) and Smad3 mRNA was increased (p<0.01) and Smad7 mRNA expression was decreased in SHR control group (p<0.01). High- and middle-dose puerarin decreased the expression of TGF-ß(1) and Smad3 mRNA (p<0.01) and increased the expression of Smad7 mRNA (p<0.05). CONCLUSION: Puerarin reduces expression of TGF-ß(1) and Smad3 mRNA and increases that of Smad7 mRNA in SHR myocardium. These changes in gene expression may be a mechanism by which puerarin provides myocardial protection from hypertension.