【摘要】 背景:已有动物实验证实超声联合对比剂能够显著增强骨髓干细胞心肌内归巢治疗心肌梗死,改善心功能。目的:体外观察超声联合对比剂对内皮祖细胞一氧化氮生成及产生途径的影响。方法:体外提取、分离和培养猪骨髓内皮祖细胞,随机分为对照组、超声组、超声对比剂组,干预后分别收集内皮祖细胞和上清液。采用硝酸还原法检测上清液一氧化氮水平,分光光度计检测内皮祖细胞一氧化氮合酶的相对活力。结果与结论:超声对比剂组内皮祖细胞上清液一氧化氮表达、内皮祖细胞诱导型一氧化氮合酶和结构型一氧化氮合酶活力均较对照组显著增加(P<0.05);超声组一氧化氮水平无明显改变,各型一氧化氮合酶活力较对照组有下降趋势,但差异无显著性意义(P>0.05);超声联合对比剂作用下,L-精氨酸和双氧水可反应生成一氧化氮,较对照组明显增加,而单纯超声无此促进作用。提示超声联合对比剂作用显著增强内皮祖细胞各亚型一氧化氮合酶活性,并可能同时促进内皮祖细胞一氧化氮非酶合成途径,是其增效骨髓干细胞治疗心肌梗死的机制之一。更多还原

【Abstract】 BACKGROUND: Animal studies have indicated ultrasound-combined contrast agents can significantly enhance the homing of bone marrow stem cells transplantation to treat myocardial infarction and improve heart function. But its mechanism is still unkown. OBJECTIVE: To observe the effect of ultrasound-combined contrast agents on the nitric oxide (NO) production and pathway by endothelial progenitor cells (EPCs) ex vivo. METHODS: Bone marrow EPCs of Chinese minipigs were extracted, separated and cultured in vitro. The EPCs were divided to three groups: control group, ultrasound group and ultrasound-combined contrast agents group. After intervention, the NO concentration in the supernatant of EPCs and nitrogen synthase (NOS) relative activity were measured by nitrate reduction and spectroscopy, respectively. RESULTS AND CONCLUSION: Compared with the control group, NO concentration in the supernatant of EPCs and NOS relative activity of EPCs were enhanced in the ultrasound-combined contrast agents group (P < 0.05), but no changed in ultrasound group (P > 0.05). Ultrasound-combined contrast agents increased the NO production in the solution containing L-arginine and hydrogene peroxide,, but single ultrasound had no effect. Results suggested that ultrasound-combined contrast agents can increase NO generation by enhancing the NOS activity and non-enzymatic NO synthesis of EPCs. These may be one of the mechanisms of the ultrasound-combined contrast agents enhancing the effect of stem cells transplanted to treat myocardial infarction.更多还原