Morphological and functional changes of the rat parotid glandular cells by clipping and reopening the parotid duct, using HAM8 antibody.

The purpose of this experiment is to examine the proliferative process of rat acinar cells after parotid duct ligation and reopening. Two experimental groups were observed. The first group was killed from 0 to 14 days after the duct ligation. In the second group, the duct was clipped for 14 days, and it was reopened. Following a period of from 2 to 28 days after removal of the clip, the glands were removed to perform a histological analysis, including hematoxylin-eosin (HE), immunofluorescent staining using HAM8 antibody, which recognizes connexin 32, and transmission electron microscopy (TEM). In the experimental gland from the 1st group at 6 days after ligation (I-6D), the acinar cells disappeared. In the tissue from the 2nd group 8 days after reopening (II-8D), newly formed acinar cells were found again. Lobular structure of the parotid glands recovered in the II-21D. HAM8 signals were observed between normal acinar cells, while they declined in the tissue from I-1D, and they were not observed in the I-2D. HAM8 signals were first observed in the II-25D and then subsequently returned to normal levels in the II-28D. These results suggest that the intercellular communication and functional recovery was not complete 25 days after reopening of the duct.In conclusion, the recovery of the acinar structure was recognized during an extended period of duct ligation, however, a time lag between the morphological and functional recovery was found to exist.