Objective: To investigate the impact of n-3 polyunsaturated fatty acid (n-3 PUFA) on function and expression of store-operated calcium channels (SOCC) in coronary artery smooth muscle cells (SMC) derived from diabetic rat. Methods: A total of 180 healthy male Sprague-Dawley (SD) rats were randomly divided into normal group (N, n=45), placebo-treated diabetic group (D, n=45), lose dose n-3 PUFA treated diabetic group (DL, n=45) and high dose n-3 PUFAs treated diabetic group (DH, n=45). Streptozotocin-induced diabetic rat animal model was established by two consecutive intraperitoneal injections. After modeling, rats in group DL and DH were treated with 10 mg·kg(-1)·d(-1) and 50 mg·kg(-1)·d(-1) n-3 PUFAs respectively per gavage for eight weeks. After eight weeks, rat coronary artery SMC was isolated by enzyme digestion. Changes of cytosolic calcium concentration in coronary artery SMC were examined by calcium fluorescence imaging technique, coronary artery tension was detected by myograph system, and protein expressions of SOCC on coronary artery SMC were measured by Western blot. Results: SOCC induced ΔF340/F380 of group N, D, DL and DH were 0.425±0.023, 0.838±0.037, 0.342±0.052 and 0.364±0.045 respectively, which was significantly lower in group N, DL, DH than in group D (P<0.05). SOCC induced changes of tensions were 0.94±0.09, 1.95±0.18, 1.35±0.24 and 1.01±0.18 in the group N, D, DL and DH, respectively, which was significantly lower in group N and DH than in group D (P<0.05). Protein expressions of STIM1, Orai1 and TRPC1 were significantly higher in diabetic rat coronary SMC than in group N (P<0.05). STIM1 protein expressions were significantly lower in group DL and DH than in group D, and Orai1 and TRPC1 protein expressions were similar among group. Conclusions: Coronary artery tension, cytosolic calcium concentration and protein expressions of SOCC are higher in diabetic rat coronary artery SMC when compared with normal rats. n-3 PUFA intervention could downregulate the protein expression of SOCC, reduce cytosolic calcium concentration and coronary artery tension, and is protective to the diabetic injury in coronary artery.
目的： 探讨n-3多不饱和脂肪酸（n-3 PUFA）对糖尿病大鼠冠状动脉平滑肌细胞（SMC）上钙库操纵性钙通道（SOCC）的功能和表达的影响。 方法： 选用健康清洁级雄性SD大鼠共180只，按完全随机分组法分为正常组（N组）、未干预糖尿病组（D组）、低剂量n-3 PUFA干预糖尿病组（DL组）和高剂量n-3 PUFA干预糖尿病组（DH组），每组45只。采用链尿霉素连续2次腹腔注射建立1型糖尿病大鼠动物模型，成模后DL组和DH组大鼠分别按每日10 mg/kg和50 mg/kg n-3 PUFA灌胃，N组和D组每日相同剂量生理盐水灌胃，持续8周。采用三步酶消化法急性分离获取大鼠冠状动脉SMC；细胞内Ca(2+)荧光成像技术测定SOCC引起的冠状动脉SMC内Ca(2+)浓度变化（ΔF340/F380）；血管张力测定技术测定SOCC引起的冠状动脉张力变化；Western blot测定冠状动脉SMC上基质交联分子1（STIM1）、钙释放激活钙通道蛋白1（Orai1）及瞬时受体电位C通道1（TRPC1）表达情况。 结果： N、D、DL和DH组冠状动脉SMC上SOCC引起的ΔF340/F380值分别为0.425±0.023、0.838±0.037、0.342±0.052和0.364±0.045，N、DL和DH组的ΔF340/F380明显低于D组（P<0.05），DL组和DH组间差异无统计学意义（P>0.05）。4组SOCC引起的冠状动脉张力变化分别为0.94±0.09、1.95±0.18、1.35±0.24和1.01±0.18，N组和DH组的冠状动脉张力低于D组（P<0.05），DL和D组间差异无统计学意义（P>0.05）。D组冠状动脉SMC上STIM1、Orai1和TRPC1蛋白表达高于N组（P均<0.05），DL组和DH组的STIM1蛋白表达低于D组（P<0.05），各组Orai1和TRPC1表达差异无明显意义（P>0.05）。 结论： 糖尿病时大鼠冠状动脉SMC上SOCC表达增加，细胞内Ca(2+)浓度增加，冠状动脉张力增加，n-3 PUFA可以下调糖尿病大鼠冠状动脉SMC上SOCC的表达，降低细胞内Ca(2+)浓度和冠状动脉张力，对糖尿病冠状动脉起保护作用。.
Keywords: Calcium channels; Coronary vessels; Diabetes; Fatty acids, unsaturated; Myocytes, smooth muscle.