Factor S M, Robinson T F
Department of Pathology, Albert Einstein College of Medicine, Bronx, New York.
Lab Invest. 1988 Feb;58(2):150-6.
A complex connective tissue framework exists in mammalian hearts that surrounds and interconnects individual myocytes and fascicles of cells. Recent evidence suggests that this connective tissue plays a role in maintaining shape, modulating contractile forces, and mediating elastic recoil during cavity filling and contraction. In order to analyze the involvement of connective tissue in pump contraction and recoil, we examined silver impregnated connective tissue in rat hearts which spontaneously jet through fluid ex vivo by contracting their cavities forcefully and then sucking fluid for the next cycle, and compared them to frog hearts which beat actively under the same conditions, but do not demonstrate jet propulsion. A further analysis was carried out in unrelated but analogous models: the squid and octopus. The former jets rapidly through the ocean, while the latter moves sinuously along the seabed. We observed highly interconnected myocytes in the rat heart, whereas frog myocytes are individually wrapped by connective tissue but are not interconnected. The squid mantle muscle is surrounded by a complex connective tissue grid that is tethered to each muscle cell, whereas the octopus mantle muscle cells are surrounded by connective tissue but are not tethered. These observations suggest that myocyte connective tissue tethering may be necessary for muscle cavities to generate forceful and coordinated contractions sufficient for rapid ejection and suction of fluid.
哺乳动物心脏中存在一个复杂的结缔组织框架，它围绕并连接单个心肌细胞和细胞束。最近的证据表明，这种结缔组织在维持心脏形状、调节收缩力以及在心室充盈和收缩过程中介导弹性回缩方面发挥作用。为了分析结缔组织在心脏泵血收缩和回缩中的作用，我们检查了大鼠心脏中经银浸染的结缔组织，这些大鼠心脏在体外通过有力收缩心室然后抽吸液体进行下一个循环，从而自发地喷射流体，我们将其与在相同条件下积极跳动但不表现出喷射推进的青蛙心脏进行比较。在不相关但类似的模型（鱿鱼和章鱼）中进行了进一步分析。前者在海洋中快速喷射，而后者沿着海床蜿蜒移动。我们观察到大鼠心脏中的心肌细胞高度相互连接，而青蛙的心肌细胞被结缔组织单独包裹但不相互连接。鱿鱼的外套膜肌肉被一个复杂的结缔组织网格包围，该网格与每个肌肉细胞相连，而章鱼的外套膜肌肉细胞被结缔组织包围但不相连。这些观察结果表明，心肌细胞与结缔组织的连接对于肌肉腔室产生足以实现快速射血和抽吸液体的有力且协调的收缩可能是必要的。
