心肌组织和一些细胞器快速冷冻后的结构变化

Ultrastructural Changes of Heart Muscle and Some Organells in Rats after Rapid Freezing

作者应用低温快速冷冻技术对心肌组织及一些细胞器的冷冻损伤过程及损伤机理作了较全面的探讨。取大鼠心室部位,用振动切片机切成100～150μm厚的薄片,采用Reichert-Jung弹射式冷冻仪KF-80将切成片状的样品快速插入冷冻剂Freon 22中冷冻。被冷冻后的样品迅速转移到置换剂丙酮中并保持温度在:-80℃(28h)、-60℃(48h)、-20℃(12 h)和4℃(1 h)。经快速冷冻后的心肌组织在表层到深度约20μm的范围内,结构保存很好,无任何冰晶。30μm深度时,线粒体嵴,细胞间质和肌丝受到冷冻损伤。50μm深度以后,组织结构基本上全部被冰晶破坏。结果表明,心肌组织在快速冷冻后,细胞间质和线粒体嵴对冰晶最为敏感,尔后是肌丝和细胞核,质膜最不易遭受冷冻损伤。

We report in detail ultrastructural changes and freezing damage mechanism about heart muscle and some organelles after rapid freezing. The ventricles of rat heart were cut pieces about 100-150/μm by microsiicer. The pieces were quickly injected liquid cryogen Freon 22 by Reichert-Jung spring-assistant mechanism (KF-80). The specimens frozen were rapidly transferred into substitution medium aceton and kept at -80℃(28h), then -60℃ (48h),-20℃(12h)and 4℃ (1 h). The structures of specimens frozen were well and there were no ice crystals in the area of the tissue frozen surface to 20μm depth. However, there were freezing damages in mitochondrial crista, intercellular substance and muscular fibre in the tissue surface to 30μm depth. The structure of tissue was destroyed by ice crystal over 50μm depth in the tissue. The results suggest that intercellular substance and mitochondrial crista are the most sensitive to ice crystal damage after rapid freezing of heart tissue, then the less sensitive are muscular fibre and nucleus. The unit membrane is not easy to be damaged by ice crystal.