Organization of the Interstitial Component of Gallbladder Muscle Tissue in Guinea Pigs

Interstitial cells of Cajal (ICCs) and ICC-like cells have been described by various authors in the muscle tissue of atria, bronchi, pancreas, mammary gland, ureter, and placenta. It is assumed that these cells have a significant influence on the regulation of spontaneous rhythmic activity of smooth myocytes (SMs) of internal organs. However, the question of clear cytological definitions of these cells remains open. The purpose of the research was to identify ICCs in various parts of the muscular coat of the gallbladder and analyse the ratio of ICCs, SMs and ICC-like cells – telocytes (TCs) – in the studied sections. Materials and methods. Fragments of the muscular coat of the gallbladder wall in three sections – neck, body and fundus – obtained from 5 guinea pigs were examined. All the animals were put on a standard diet and kept in a special room. An immunocytochemical study was performed for the c-kit tyrosine kinase receptor (CD117). To calculate the ratio of SMs, ICCs and TCs we analysed isolated cells obtained using the original method of targeted cell dissociation, which allows us to identify the morphological characteristics of cells. Results. By means of light microscopy, we identified cellular elements in the composition of SMs of the gallbladder wall that differ significantly in their morphology from classical myocytes. According to the quantitative analysis, the ratio of GMs, ICCs and TCs in different sections of the gallbladder varies. The absence of specific markers for TC identification indicates heterogeneity of their population or their ability to differentiate into other cell types. It can be stated that there is no clear understanding of the structural and functional organization of ICCs and TCs or their probable role in maintaining the structural homeostasis of organs, which necessitates further research.