A Preliminary Study On The Biological Change Of Myoepithelial Cells During Atrophy Of Rat Parotid Gland

ObjectiveTo investigate the changes in number and distribution of myoepithelial cells during atrophy of the rat parotid gland.MethodsAtrophy of the right parotid was induced by ligating the stensen duct of rats.Histological changes of parotid glands were examined by HE staining during each step of glandular atrophy at time zero(control) and1、3、5、7、14、21、30、60、100、150days after ligation; Immunohistochemical labelling for myoepithlial cells was also performed to study the changes in number and distribution of myoepithelial cells during atrophy of the rat parotid gland.ResultsMorphological analysis showed disappearance of the acini at5days and a gradual decrease and fibrosis of the glandular lobules accompanied by the occurrence of duct-like structures. Quantitative analysis of myoepithelial cells showed significant increase in the number up to day5post-ligation, then followed by gradual increases at a low level, at last it was followed by a rapidly decrease after the total number reached the peak by the100days, In addition, the distribution of myoepithelial cells revealed the acini and intercalated ducts were covered by myoepithelial cells ranged in shape from spindle-shaped to stellate in the early phase of atrophy, while spindle-shape myoepithlial cells were located at the periphery of duct-like structures in the later phase of atrophy.ConclusionMyoepithelial cells show regular changes during atrophy of the rat parotid gland. Myoepithelial cells proliferate rapidly up to day5post-ligation,then followed by gradual increases at a low level, at last it was followed by a rapidly decrease after the total number reached the peak by the100days,...