大蒜素对自发性高血压大鼠心肌I_(to)重构的影响

Effect of allitridum on remodeling of the transient outward potassium current of ventricular myocytes of spontaneously hypertensive rats

本研究旨在探讨大蒜素(All)对自发性高血压大鼠(SHR)肥厚心肌细胞瞬时外向钾电流(Ito)的作用。应用All注射液(7.5和15.0 mg·kg-1)对SHR腹腔注射8周。双酶法分离各组大鼠心室肌细胞,利用膜片钳技术观察All对心肌肥厚指标及Ito的作用。结果显示,All对SHR肥厚心肌有明显的逆转作用,使心室肌细胞的膜电容显著降低。高、低剂量组均使SHR重构的Ito电流得以恢复,在+50 m V电压下,分别使Ito从18.23±3.64升至36.47±5.42 p A/p F(P<0.01)和25.17±2.86 p A/p F(P<0.01),与WKY(Wistar Kyoto)大鼠对照组接近。此效应与All减少通道稳态和关闭态失活、加速失活后恢复有关。本文发现All可降低SHR肥厚心肌心室肌细胞Ito的重构。

We aimed to study the effect of allitridum （All） on the transient outward potassium current （/to） of ventricular myocytes of spontaneously hypertensive rats （SHR）. Totally 30 male SHRs were randomly divided into three groups： low-dose All group （7.5 mg·kg^-1）, high-dose All group （15.0 mg ·kg^-1） and normal saline group. The other l0 sex and age matched Wistar-kyoto rats （WKY） were also taken as control group （WKY group）. All animals received ip administration for 8 weeks. The dual enzymatic method was used to separate single ventricular myocyte from animals. Patch-clamp technique was used to record/to and analyze the effect of All on the current. It was shown that the left ventricular hypertrophy of SHR was reversed significantly by All. Furthermore, the density of/to was recovered in both high and low dose All groups. The peak current densities of/to were enhanced from 18.23±3.64 to 25.17±2.86 pA/pF （P〈0.01） and 36.47±5.42 pA/pF （P〈0.01） at ＋50 mV by All 7.5 mg·kg^-1 and 15.0 mg·kg^-1, respectively, which was not significantly different with WKY group. The effect was associated with positive shift of the steady-state, close-state inactivation, and shortened recovery from inactivation of/to. It is concluded that All decreases the remodeling of/to of ventricular hypertrophic myocytes of SHR.