IN VIVO ANGIOGENESIS IN ADULT RAT SKELETAL MUSCLE : EARLY CHANGES IN CAPILLARY NETWORK ARCHITECTURE AND ULTRASTRUCTURE

摘要: The individual structural stages in capillary growth have been identified during development and under pathological circumstances adults (wound healing, tumors), but there are no data to indicate whether these steps similar when angiogenesis is induced a fully differentiated microvascular bed normal, uninjured adult skeletal muscle. In this study changes ultrastructure were correlated with density network morphology elucidate the sequelae of rat extensor digitorum longus (EDL) muscle whose activity was increased by stimulation at 10 Hz (8 h/day). This resulted an capillary/fiber (C/F) ratio (based on staining for alkaline phosphatase) after 4 days; 7 days C/F further, approximately 50%. endothelium both EDL hallucis proprius (EHP) control muscles 2 stimulation, whereas endothelial cells some capillaries stimulated revealed signs metabolic activation such as proliferation organelles (Golgi apparatus, endoplasmic reticulum, ribosomes mitochondria) fewer pinocytic vesicles. Luminal surfaces often irregular numerous pseudopodial processes. Basement membranes always present amorphous regions observed, particularly near pericyte Unusually small profiles, either slit-like lumen or cisternae lumen, probably represented sprouts. interstitium contained collagenous granular extracellular matrix surrounding capillaries, activated fibroblasts which closely apposed many capillaries. Capillary EHP also evaluated confocal microscopy using whole mounts. complex pattern vessels underwent remodelling between resulting more tortuous sprouts loops. These combined observations suggest that may occur combination sprouting, intussusceptive elongation; also, occurs same time disturbance basement earliest phase bed. postulated connection shear stress and/or wall tension, demonstrated previously.