Tavakoli Reza, Nemska Simona, Jamshidi Peiman, Gassmann Max, Frossard Nelly
Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich;
Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich; Laboratoire d'Innovation Thérapeutique, UMR7200, Université de Strasbourg - CNRS.
J Vis Exp. 2017 Sep 25(127):56231. doi: 10.3791/56231.
Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH. Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%. In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.
小鼠横向主动脉缩窄（TAC）是用于压力超负荷诱导的左心室肥厚（LVH）及其向心力衰竭进展的实验研究中最常用的外科技术之一。在大多数已报道的研究中，该手术需要对动物进行插管和通气，这使得手术要求高、耗时且增加了动物的手术负担。本方案的目的是描述一种简化的微创TAC技术，无需对小鼠进行插管和通气。强调了该技术的关键步骤，以实现低死亡率和高效诱导LVH。雄性C57BL/6小鼠（10周龄，25 - 30 g，n = 60）通过单次腹腔注射氯胺酮和赛拉嗪的混合物进行麻醉。在一只自主呼吸的动物身上，进行3 - 4 mm的上半部分胸骨切开术后，将一段穿过结扎辅助器针眼的6/0丝线从主动脉弓下方穿过，并在一根钝头的2G7号针上打结。假手术动物接受相同的手术准备，但不进行主动脉缩窄。心脏/体重比显著增加证明了该手术诱导LVH的有效性。该比值在手术后第3、7、14和28天获得（每组和每个时间点n = 6 - 10）。使用我们的技术，与假手术动物相比，从第7天到第28天在TAC小鼠中观察到LVH。手术死亡率和晚期（超过28天）死亡率均非常低，为1.7%。总之，我们在小鼠中采用的具有成本效益的微创TAC技术手术死亡率和术后死亡率非常低，且在诱导LVH方面效率很高。它简化了手术过程，减轻了动物的负担。按照本方案中描述的关键步骤可以轻松完成该手术。
