槲皮素对血管紧张素Ⅱ致培养乳鼠心肌细胞肥大的抑制作用

目的:研究槲皮素(Quercetin,Que)对血管紧张素Ⅱ(Aug Ⅱ)诱发培养乳鼠心肌细胞肥大的抑制作用及机制。方法:分别用~3H]胸苷、~(14)C]尿苷和~3H]酪氨酸标记测定DNA、RNA和蛋白质合成;用Lowry法测定蛋白质含量;用组蛋白ⅢS、γ-~(32)P]ATP与蛋白激酶C(PKC)酶液一起保温测定PKC活性;用聚谷氨酸·酪氨酸(4:1)多肽、γ-~(32)P]ATP与酪氨酸蛋白激酶(TPK)酶液一起保温测TPK活性。结果:Aug Ⅱ作用于心肌细胞24h后,心肌细胞总蛋白含量明显增加(P<0.01),~(14)C]尿苷和~3H]酪氨酸掺入量明显增加(P<0.01),而~3H]胸苷掺入量未见增加(P>0.05);Aug Ⅱ作用30min后,心肌细胞PKC和TPK活性明显增加。Que(1-100μmol/L)能剂量依赖性地抑制Ang Ⅱ所致心肌细胞总蛋白含量、~(14)C]尿苷和~3H]酪氨酸掺入量、PKC及TPK活性的增加。结论:Que可抑制Aug Ⅱ致培养乳鼠心肌细胞肥大,该作用与抑制PKC及TPK活性有关。

Inhibitory effect of quercetin on cultured neonatal rat cardiomyocytes hypertrophy induced by angiotensin II

AIM: To study the inhibitory effect of quercetin on cultured neonatal rat cardiomyocytes hypertrophy induced by angiotensin II (AngII) and its mechanism. METHODS: DNA, RNA, and protein synthesis were measured by incorporation of 3H]thymidine, 14C]uridine, and 3H]tyrosine, respectively. Protein content were measured by Lowry's method. Protein kinase C (PKC) activity was assayed by incubating PKC with histone IIIS and gamma-(32)P]ATP. Tyrosine protein kinase (TPK) activity was assayed by incubating TPK with poly glutamate/tyrosine (4:1) and gamma-(32P]ATP. RESULTS: After treated with AngIIat 10 nmol/L for 24 h, total protein content was greatly increased as compared with untreated group (P < 0.01). Incorporation of 14C]uridine and 3H]tyrosine was also greatly increased (P < 0.01) respectively, while incorporation of 3H]thymidine remained unchanged (P > 0.05). Ang II strongly increased cardiomyocytes PKC and TPK activities at 30 min. Que (1-100 micromol/L) could inhibit the increase of total protein content, incorporation of 14C]uridine and 3H]tyrosine, and PKC and TPK activities induced by Ang II in concentration-dependent manner. CONCLUSION: The inhibitory effect of Que on the cardiomyocytes hypertrophy was related to its inhibitory effect on PKC and TPK.