Effects of Tanshinone ⅡA on inhibition of biological synthesis of aldosterone

Yan XIA; Chengye ZHAN; Shaojie HAN; Zhi ZHENG

ABSTRACT

BACKGROUND:

Aldosterone is an important pathogenic factor of left ventricular hypertrophy. There has been evidence that the extract of red sage root (a Chinese herb) can intervene the synthesis of aldosterone.

OBJECTIVE:

To investigate the effects of tanshinone Ⅱ A on expression of genes related to aldosterone synthesis in myocardium.

DESIGN:

A randomized and controlled trial.

SETTING:

Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology. MATERIALSThe experiment was performed at the laboratory of Emergency Department, Tongji Hospital Affiliated to Tongji Medical College,Huazhong University of Science and Technology from November 2002 to March 2004. Totally 20 male 12-week-old rats with spontaneous hypertension were randomly divided as hypertension group and tanshinone Ⅱ A group.

METHODS:

Rats in each group were injected tanshinone Ⅱ A or distilled water in the same volume respectively through caudal vein. After 12-week administration,the rats were put to death by decapitation, and the samples of myocardium were prepared. The expressions of CYP11B1mRNA and CYP11B2 mRNA, or myocardial genes related to aldosterone synthesis were examined with reverse transcriptase polymerase chain reaction (RTPCR) and referring to the amplification primers of glyceraldehydes 3-phosphate dehydrogenase (GAPDH) gene. MAIN OUTCOME

MEASURES:

The levels of CYP11B1 and CYP11B2 mRNA related to aldosterone synthesis in myocardium.

RESULTS:

Totally 20 rats were involved in the trial and all entered in the final result analysis without any loss of value. ① Quantitative analysis of expression of myocardial CYP11B1 and CYP11B2 genes in rats of two groups Taking 100bp Plus Ladder as Marker,clear amplified strands could be seen at 440bp,461bp and 336bp sites,DNA sequencing proved they were the encoding gene segments of CYP11B1,YP11B2 and GAPDH. ②Qualitative analysis of expression of myocardial CYP11B1 and CYP11B2 genes in rats of two groupsThe expressive levels of CYP11B1 and CYP1 1B2 mRNA contents in tanshinone Ⅱ A group were significantly lower than those in hypertension group (0.924±0.121 vs 1.343±0.132,P ＜ 0.05;1.017±0.119 vs 1.675±0.126,P 0.01).

CONCLUSION:

Tanshinone Ⅱ A could directly down-regulate the expression of CYP1 1B1 and CYP1 1B2 mRNA, the genes related to aldosterone syn thesis, so that it inhibited the biological synthesis of aldosterone in myocardinm, thus playing a role to resist hypertensive left ventricular hypertrophy.