基于P-SLex双靶向超声微泡在体探讨滋肾清肝方改善动脉细胞外基质Tropoelastin蓄积抗AS的机制研究

Chronic inflammation exist throughout the whole pathogenesis of atherosclerosis (AS), and it induced elastolysis (EL) and elastogenesis (EG) dysfunction of extracecellular matrix, which is the key mechanism of arterial structure remodeling and elastic recession. Zishen Qinggan Fang (ZQF) was a effective decoction established by our institution for years. Preliminary studies suggested that ZQF can affect AS arterial elasticity and renal extracellular matrix degradation. However, the effect and mechanism of ZQF on EG dysfunction are still unclear. Numerous studies in vitro have shown that tropoelastin, a precursor of EG synthetic elastin, is extremely low in the extracellular matrix of healthy arteries. However, tropoelastin can accumulate in the extracellular matrix and on the surface of endothelial cells with arterial EG dysfunction. This feature makes targeted tropoelastin molecular ultrasound imaging theoretically possible to real-time assess the EG dysfunction status of arteries in vivo. Therefore, this study intends to explore the mechanism of ZQF and its units regulating EG dysfunction in arterial extracellular matrix to intervene the occurrence and development of AS in vivo, on the ApoE-/- mice model stimulated by different pathogenic factors, and by using P-SLex double-targeted ultrasound microbubbles combined with molecular biology technology. It is expected that this study will elucidate the molecular mechanism of effective ZQF in improving the decline of arterial elasticity from the perspective of molecular imaging, and provide a new theoretical basis for the treatment of AS with traditional Chinese medicine.

慢性炎症贯穿于动脉粥样硬化（AS）发病全过程，其诱导的细胞外基质弹性蛋白的弹性降解（EL）与弹性生成（EG）功能紊乱，是动脉结构重塑及弹性衰退的重要机制。我院确有疗效的名医验方滋肾清肝方（ZQF），前期研究表明其可干预AS动脉弹性衰退及肾脏细胞外基质EL功能。然而ZQF对EG功能紊乱的影响及机制目前仍尚不明确。大量体外研究显示，EG合成弹性蛋白的前体物质tropoelastin在正常动脉细胞外基质中含量极低；然而当动脉EG功能紊乱时，tropoelastin可在细胞外基质中及内皮细胞表面大量蓄积。这一特征使得靶向tropoelastin的超声分子成像在理论上可实现活体状态下实时评估动脉EG功能紊乱状态。故本课题拟借助P-SLex双靶向超声微泡结合分子生物学技术，在不同致病因素刺激的ApoE-/-小鼠AS模型上，在体探讨ZQF及其功效单元调控动脉细胞外基质EG功能紊乱干预AS发生发展的机制。

动脉粥样硬化及动脉粥样硬化性心血管疾病严重地威胁着人类的健康。大量研究显示，动脉弹性生成功能紊乱是动脉粥样硬化发生发展的重要机制。我院经临床验证有效的滋肾清肝方（ZQF）可有效缓解动脉粥样硬化及其诱导的大血管弹性衰退，但其机制仍不十分清晰。而早期发现并积极干预动脉弹性生成功能紊乱状态有助于及时遏制动脉粥样硬化的进展，但目前对其尚缺乏有效的活体状态下的评价指标。本研究利用P-SLex及tropoelastin单抗成功构建了双靶向超声微泡--MBPT并进行了体外及体内验证，其结果显示MBPT能够实现与靶分子相对牢固的结合，其靶向黏附效能显著优于于空载微泡及单靶向对照微泡。MBPT及其超声分子成像校正后造影峰值强度参数--NVI可作为活体状态下评估大血管弹性生成功能紊乱状态的有效指标。不仅如此，进一步研究则显示，NVI在ZQF组与对照组间比较有显著差异（P<0.05）；但组方组与对照组比较，虽有NVI部分下降，但无显著的统计学差异（均P>0.05）。双靶向超声微泡MBPT可实现对ZQF干预动脉粥样硬化弹性生成紊乱状态在体疗效评估，为实现动脉粥样硬化大血管损伤提供了早期精准的影像学评价。