Gαi2C-末端肽段靶向超声造影剂的制备及靶向性评价

Preparation and targeted evaluation of GαC-terminal peptide targeted-ultrasound contrast agent

目的探讨制备携Gαi2C-末端肽段(Gαi2ctp)靶向超声造影剂的可行性及靶向性。方法根据Gαi2ctp的质量将靶向微泡分为0.5、1.5、3 mg/L三组,利用静电吸附法制备Gαi2ctp靶向微泡,通过检测微泡大小、携带率来探索其最佳结合剂量。选取最佳剂量进行动物实验,复制犬房颤模型,利用超声靶向微泡破坏技术定点爆破微泡,采用免疫荧光法检测微泡的靶向性。结果 Gαi2ctp与SonoVue微泡可通过静电吸附法有效结合。1.5 mg/L组静置0.5、1、2 h Gαi2ctp靶向微泡携带率高于3 mg/L组,差异均有高度统计学意义(均P <0.01);1.5 mg/L组与0.5 mg/L组静置0.5、1、2 h Gαi2ctp靶向微泡携带率比较差异无统计学意义(P> 0.05)。1.5 mg/L组洗涤前后Gαi2ctp靶向微泡携带率比较,差异无统计学意义(P> 0.05)。3 mg/L组和0.5 mg/L组洗涤后Gαi2ctp靶向微泡携带率低于携带前,差异均有高度统计学意义(均P <0.01)。犬左心房及肺静脉冰冻切片荧光显微镜下显示,实验组(携1.5 mg/L Gαi2ctp靶向微泡)犬左心房及肺静脉可见明亮的橙红色荧光表达,对照组(SonoVue空白微泡)未出现橙红色荧光。结论本研究成功制备Gαi2ctp靶向超声造影剂,其大小均一、性质稳定,并可与靶组织特异性结合。

Objective To explore the feasibility and targeting of Gαi2C-terminal peptide(Gαi2 ctp) targeted-ultrasound contrast agent. Methods The targeted microbubbles were divided into three groups of 0.5, 1.5, 3 mg/L according to the quality of Gαi2 ctp. Gαi2 ctp-targeted microbubbles were prepared by electrostatic attraction way, and the optimal combined dose was explored by detecting the size, carrying rate of microbubbles. The best dose was choosed for animal experiments by making a canine atrial fibrillation model. Ultrasound-targeted microbubble destruction was used to destroy the microbubbles and immunofluorescence method was used to detect the targeting of the microbubbles. Results Gαi2 ctp and SonoVue microbubbles could be combined effectively by electrostatic attraction way. The Gαi2 ctp targeted microbubble carrying rate of 1.5 mg/L group was higher than that of 3 mg/L group at 0.5, 1 and 2 h after standing, and the differences were highly statistically significant(all P < 0.01). There was no significant difference in the Gαi2 ctp targeted microbubble carrying rate between 1.5 mg/L group and 0.5 mg/L group after 0.5 mg/L at 0.5, 1 and 2 h(P >0.05). There was no statistically significant difference in the carrying rate of 1.5 mg/L group before and after washing(P >0.05). After washing, the Gαi2 ctp targeted microbubble carrying rate of 3 mg/L group and 0.5 mg/L group were lower than those before washing, and the differences were highly statistically significant(all P < 0.01). Frozen sections of canine left atrium and pulmnoary vein were showed that bright orange-red fluorescence expression in the left atrium and pulmnoary vein of dogs in experimental group(carrying1.5 mg/L Gαi2 ctp targeting microbubbles group), but no orange-red fluorescence was in control group(SonoVue blank group). Conclusion In this study, Gαi2 ctp-targeted ultrasound contrast agent is successfully prepared. It is uniform in size, stable in nature, and specifically binded to target tissues.