Knox Micheal, Fluckey James D, Bennett Patrick, Peterson Charlotte A, Dupont-Versteegden Esther E
University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Aviat Space Environ Med. 2004 Aug;75(8):692-6.
Hindlimb unloading has proven to be an effective model for studying the physiological effects of spaceflight. However, using current methodologies, maintenance of adult rats in hindlimb unloading for long periods is challenging. Therefore, our goal was to develop a technique allowing long-term hindlimb unloading in adult rats.
Adult male Sprague Dawley rats were assigned to control (C), control pinned (CP), and hindlimb unloaded (HU) groups. All rats were anesthetized and a stainless steel needle was inserted through the skin in the ventral side of the tail of CP and HU groups. A cable was inserted through the needle, wrapped around to the dorsal side, secured, and stabilized with casting tape. HU rats were hindlimb suspended for 28 d by attaching the cable to an adjustable bar, resulting in a 30 degrees head-down tilt, and were monitored for health status and bodyweight. Fecal corticosterone levels were used as a stress index. Hindlimb muscles and adrenals were weighed.
Attrition due to animals slipping from their tail harness was eliminated. HU animals lost 9.9% bodyweight within the first 6 d of hindlimb unloading, but maintained that bodyweight the remaining 22 d. Stress levels, as measured by fecal corticosterone and adrenal weights, were not elevated significantly during suspension and muscle weights were decreased significantly.
Results indicate that this method is suitable for long-term hindlimb unloading of adult rats, providing an alternative approach to study loss of musculoskeletal mass in simulated microgravity.
后肢去负荷已被证明是研究太空飞行生理效应的有效模型。然而，使用当前方法，成年大鼠长时间进行后肢去负荷的维持具有挑战性。因此，我们的目标是开发一种允许成年大鼠长期后肢去负荷的技术。
成年雄性Sprague Dawley大鼠被分为对照组（C）、对照固定组（CP）和后肢去负荷组（HU）。所有大鼠均麻醉，在CP组和HU组大鼠尾巴腹侧皮肤插入一根不锈钢针。将一根缆线穿过针，缠绕到背侧，固定并用铸型胶带稳定。通过将缆线连接到可调节杆上，使HU组大鼠后肢悬吊28天，导致头向下倾斜30度，并监测其健康状况和体重。粪便皮质酮水平用作应激指标。称量后肢肌肉和肾上腺重量。
消除了动物从尾部固定装置滑落导致的损耗。HU组动物在后肢去负荷的前6天内体重减轻了9.9%，但在剩余的22天内保持该体重。通过粪便皮质酮和肾上腺重量测量的应激水平在悬吊期间没有显著升高，肌肉重量显著降低。
结果表明该方法适用于成年大鼠的长期后肢去负荷，为研究模拟微重力下肌肉骨骼质量损失提供了一种替代方法。
