Fine structure of the cilia in the pancreatic duct of WBN/Kob rat.

We observed the cilia in pancreatic ducts (intraductal cilia) with scanning and transmission electron microscopy (SEM and TEM), using male WBN/Kob rats (W/K), which are the spontaneously developed chronic pancreatitis models with stasis of pancreatic juice, and male Wistar rats as control. By SEM observations, the lengths of cilia in interlobular ducts of 18-mo-old W/K were demonstrated to elongate markedly. By TEM observations in the controls, cross-sections of the intraductal cilia were demonstrated to present various numbers of microtubules (those with seven, eight, or nine microtubules accounted for 83.3% of all). There was no significant difference between W/K and controls in the number of microtubules in the cross-sections of intraductal cilia: the intraductal cilium core was provided with nine microtubules, which were different from the number of microtubules encountered within the cilium core of other ciliated cell (i.e., bronchial epithelium, and so forth), and their number in the cross-section of intraductal cilium decreased at a distal portion. Though some of their cross-sections revealed deformities of ciliary membranes and disarrangements of microtubular complex, there was no significant difference in their incidence between both rats. These findings suggest that the intraductal cilia have different functions from the ciliated cells' cilia, and W/K has the elongated intraductal cilia without internal structural change.