吳郭魚成魚心室肌細胞之超微構造

Abstract

本研究是利用電子顯微鏡觀察吳郭魚之心室及其經酵素分離之心室肌細胞的超微構造。在超微構造的觀察，心室是由狹長、分枝之心肌細胞構成，細胞呈典型的脊椎動物心肌細胞構造，其內肌原纖維可明顯的區分A帶、I帶、Z-線和H區，惟較高等脊椎動物不發達。肌原纖維由平行的肌絲組成，通常位於細胞周圍，而細胞核、粒線體和其他胞器位在細胞中央；肌間盤通常橫在心肌細胞的Z-線上；肌漿網不是很發達。魚心室細胞內沒有橫管（t-tube）系統，但是肌漿膜有固定向兩鄰近的肌原纖維的Z-線接觸凹入或膨大的現象。分離的單一心肌細胞呈紡錘形，大小長約140-190 μm、寬約3-5 μm。由超微構造的研究，顯示分離的單一心室肌細胞與心室組織細胞相似，細胞內含有構造完整的胞器。所不同的是在游離細胞的表面可觀察到一些泡狀突起，突起內主要構造為粒線體，偶爾可見是細胞核或只有細胞質的突出。

Ultrastructures of the both ventricular cardiomyocyte in the Tilapia heart and it's enzymatically isolated cardiomyocyte were described with electron microscopes. The ventricle contains narrow, branch spindle-shape cells. The myofibrils in the cardiomyocytes exhibit a typical vertebrate pattern with distinctive A-bands, I-bands, Z-lines and H-zone, but they appeared less prominent than that in higher vertebrates. In cardiomyocytes the myofibrils usually were located in peripheral region, whereas nucleus, mitochondria, and other organelles were in the center. Intercalated disks were often found, and transverse part on the Z-line between two cardiomyocytes. Sarcoplasic reticulum was a not well developed as in vertebrate. The sarcolemma was firmly attached to Z-line of myofibrils between the neighbor cardiomyocytes without a distinct T system. In vitro, the isolated cardiomyocytes maintained in spindleshape. The length and width of these myocytes were 140-190 μm and 3-5μm, respectively. Ultrastructural studies showed that the isolated myocytes contact and contained well organized organelles such mononucleus, mitochondria, sarcoplasmic reticulum, and myofilaments, Several blebs in irregular shapes were observed on the cell surface and they contained a lot of mitochondria and few nucleus sometimes.