茶多酚对正常大鼠及糖尿病大鼠右室乳头肌收缩功能的影响

目的：研究不同浓度的茶多酚（TP）对于正常大鼠及糖尿病大鼠成模后第6周、第8周右室乳头肌收缩功能的影响。 方法： 以四氧嘧啶复制糖尿病大鼠模型，将成模后第6周、第8周糖尿病大鼠右心室乳头肌游离，置于氧合台氏液中，电刺激状态下，记录乳头肌收缩功能，观察不同浓度的茶多酚的影响，并与对照组大鼠进行比较。 结果： 成模糖尿病大鼠第6周时舒张1/2间期延长（P<0.05），收缩速度:+dT/dtmax，-dT/dtmax均降低(P<0.01,P＜0.05)，至第8周张力增量，收缩速度:+dT/dtmax，-dT/dtmax降低（P<0.01）,舒张1/2间期延长（P<0.01）。正常SD大鼠和糖尿病大鼠右室乳头肌给予不同浓度的茶多酚，在15-120 mg/L的浓度范围内，茶多酚对于正常大鼠可以产生正性肌力作用;虽然糖尿病6周大鼠的右室乳头肌收缩功能有所降低,但对茶多酚产生与正常大鼠相似的反应，而糖尿病8周的大鼠对于茶多酚无明显反应。 结论： 茶多酚应用于早期的糖尿病性心肌病，可以产生正性肌力作用，但是对于有严重的心肌损害的糖尿病大鼠心肌，不能产生正性肌力作用。

Effect of tea polyphenols on the contractile function of the papillary muscles of right ventricle in diabetic rats

AIM: To investigate the effect of tea polyphenols (TP) on the contractile function of the papillary muscles of right ventricle in the sixth and eighth week diabetic rats and the control rats. METHODS: Rats were induced to diabetic by an intravenous injection of alloxan. The papillary muscles of right ventricle in the sixth and eighth week diabetic rats were segregated and superfused with oxygenated Tyrode' s solution. The contractile function and functional change under the electric stimulation state was recorded and compared between diabetic group and control group. RESULTS: 1 /2 diastole interval elongation ( P < 0.05) and the depression of dT/dtmzx( P < 0.01) and - dT/dtmax(P < 0.05) of the papillary muscles of right ventricle were showed in the 6th week diabetic rats, while further damages, such as tension addition ( P < 0.01), 1/2 diastole interval elongation ( P < 0.01) and the depression of dT/dtmax(P< 0.01) and - dT/dtmax(P< 0.01) in 8th week diabetic rats were also observed. TP at certain concentrations (15-120 mg/L) did not produce any effect on the 8th week diabetic rat's papillary muscle, but the positive muscle strength has been showed in the control rats and the sixth week diabetic rats. CONCLUSIONS: TP produces the positive muscle strength in the early diabetic cardiomyopathy, but has no beneficial effect on serious impaired diabetic myocardium.