Hyaluronan applied to the middle ear mucosa prior to fixation improves the morphological quality

In a previous study, it was noted that immersion-fixed middle ear mucosa appeared better preserved if treated with hyaluronan (hyaluronic acid, HA) prior to fixation. The present study showed that HA instilled into the middle ear caused the epithelial cells to emerge more brilliant--when stained with toluidine blue--but did not hinder minor autolytic changes from occurring. The precise molecular or biochemical event or events that cause the brilliance are not known at present. HA did not cause any severe structural alterations of the mucosa.