大鼠胃壁内毛细淋巴管的超微结构

ULTRASTRUCTURE OF THE INTRAMURAL LYMPH CAPILLARIES OF THE STOMACH IN THE RAT

The intramural lymph capillaries of the stomach in the rat were studied by electron microscopy in order to obtain information regarding to their ultrastracture and the possible mechanisms of lymph formation. These analyses were performed with aid of the medical image analysis system. Ultrastructurally, the lymph capillaries of the stomach were similar to those described in other organs. The endothelial lining was thin, non-fenestrated and no pericytes, and lacked a continuous basal lamina. The cytoplasmic organelles including mitochondria, rough endoplasmic reticulum, lysosomes and vesicles were observed. 56 intercellular junctions were examined. Three morphological types of them were seen, i. e. end to end, overlapping and interdigitating types. Of these, 1.8% were of the end to end type, 73.2% were the overlapping type (7.3% with junctional complexes) and 25% were interdigitating type. Open junctions (>30nm) accounted for 3.5% of these contacts. The mean maximum diameter of the vesicles was 49.4 nm, the volume density was 0.023 and profile density was 36. The distribution of the vesicles was as following: 29.1% opened onto or touched the abluminal membrane, 44,9% without visible connection to either surfaces, 26% opened onto or touched the luminal membrane. It was concluded that the mechanism of lymph formation in the stomach seems to be different from that of those organs such as heart, liver, kidney and thyroid. The present study suggested that the intercellular pathway may act as the primary route for lymph formation and macromolecule transportation, and the intracytoplasmic vesicular system may also play certain role in the transport of macromolecules.