A Preparation for the invivo Study of Capillary and Fiber
The mammalian diaphragm is adapted superbly to achieve high sustained rates of ATP turnover. Maximal blood flows, capillary volume and oxidative enzyme capacities far exceed those found in other skeletal muscles. Furthermore, decrements in diaphragm function consequent to disease radically impact the physiological capabilities of the individual. The rat costal diaphragm is only 200–500 μm thick depending on the imposed stretch. Thus, structurally the diaphragm lends itself to transillumination and optical examination. A novel preparation for the in vivo examination of the diaphragm microcirculation has recently been described by Boczkowski and colleagues and facilitates examination of vessel diameters and the presence or absence of blood flow (Microvasc. Res. 40, 1990). The purpose of the present report is to detail modifications which permit: a) Avoidance of the Trendelenburg position which can invoke myogenic and sympathetic effects on skeletal muscle microcirculation (Segal and Puri, Med. Sci. Soorts Exerc. 25, 1993. b) Avoidance of severe tissue stretching. c) Visualization of muscle sarcomeres and adjacent capillaries. d) Measurement of capillary red blood cell (RBC) velocity.