卡托普利对甲状腺素性心肌肥厚大鼠血管平滑肌收缩反应的影响

Influences of Captopril on Vascular Smooth Muscle Contractions in Thyroxine Cardiac Hypertrophic Rats

目的 研究卡托普利对甲状腺素 (THY)性心肌肥厚大鼠血管平滑肌的内钙释放和外钙内流所致收缩的影响。方法 大鼠连续 10d每天ipTHY 0 .5mg/kg造成心肌肥厚及血管病变模型 ,卡托普利在d8,9,10po 5 0、10 0mg/kg给药 ,在d11,大鼠的胸主动脉进行由高钾引起的三相收缩 ,比较在正常组、THY肥厚组和卡托普利组大鼠血管平滑肌的内钙释放和外钙内流所致收缩的变化。结果 肥厚组的心室 /体重 (VW /BW )指数比正常组明显升高 ,而卡托普利能显著降低之 ;THY心肌肥厚大鼠的平滑肌由内钙释放和外钙内流所致的收缩百分率比正常组都显著增加 ,而卡托普利剂量为 5 0mg/kg时对由外钙内流所致的收缩比正常组和肥厚组的显著降低 ,对内钙释放无影响 ;卡托普利剂量为 10 0mg/kg时对由内钙释放所致的收缩比正常组和肥厚组的显著降低 ,对外钙内流所致的收缩与肥厚组比显著减少。结论 卡托普利对THY性心肌肥厚大鼠血管平滑肌高钾引起的收缩反应有显著抑制作用 。

AIM The purpose is to investigate influences of captopril on vascular smooth muscle (VSM) contractions induced by intracellular Ca\+\{2+\} release and Ca\+\{2+\} entry in THY (L thyroxine) cardiac hypertrophic rats. METHODS A cardiac hypertrophy (CH) model was produced by ip THY 0.5 mg/kg/d for 10 d. Rats were divided into control group, CH group (treated with THY for 10 d) and 2 captopril groups (treated with THY for 10d and administering captopril 50, 100 mg/kg po on d 8, 9, 10, respectively). On the 11th day, the ventricular index, VW/BW (mg/g) was obtained and compared with that of control group. The rat aortic rings were suffered to 3 phases of contractions.RESULTS The ventricular index was higher in CH rats than that of in control rats, three days treatment of the CH with captopril at doses of 50 and 100 mg/kg significantly reduced the ventricular index. The intracellular calcium release of VSM significantly enhanced in CH and captopril 50 mg/kg groups, while captopril 100 mg/kg suppressed the enhanced intracellular Ca\+\{2+\} mobilization induced by THY. The Ca\+\{2+\} entry of VSM also higher in CH group vs. control. Captopril (50 and 100 mg/kg, po) significantly inhibited the contractions caused by Ca\+\{2+\} entry. CONCLUSION Captopril could inhibit significantly VSM contractions caused by high potassium in THY cardiac hypertrophic rats. The mechanism may involve the suppression of the intracellular calcium mobilization and calcium entry in VSM.