イヌ顎下腺における経導管的逆行性注入異物の消長に関する電顕的検索

Abstract

It is generally accepted that either acute ductal obstruction or ductal filling with contrast medium during sialography increases intraluminal pressure and the substance accumulated in the luminal system is responsible for the increased intraductal pressure, but little information is available on the subseqent fate of the accumulated substance. The purpose of this study was to follow the movement of the substance accumulated intraluminally by means of retrograde injection of tracer particles.In the present study on dogs, squid ink and ferritin particles suspended in saline solution were injectedluminally via the main duct of the submaxillary salivary gland and then traced mainly at the electron microscopic level. High intraluminal pressure was established at 80 cmH2O, 130 cmH2O, and 200 cmH2O employing hydrostatic technique. Each pressure level was maintained for 5, 30, and 60 minutes.The results showed that almost all of these foreign substances penetrated into the intercellular space of acinus and ducts by passing through the intercellular junctions. These substances finally reached the interstices of the gland across the basal lamina, but the leakage from the basal lamina increased with elevation of injection pressure.On the other hand, there was via the coated pit uptake of a small quantity of squid ink accumulated in the intercellular space of the intercalated duct and thereafter it was found in the secondary lysosomes.The present observation suggests that the removal route of squid ink from the lumina can be divided into two different ways. The first route appeared to be produced mechanically by the so-called back pressure and the second route was formed by the phagocytic activity of the intercalated duct cells. However, it is still unknown whether the uptake of squid ink is physiological or pathologic.