Histological characteristics of healthy animal peritoneum

Abstract

The aim of this study was to investigate the morphological and histological characteristics of healthy animal peritoneum, with special references to its microvasculature. Biopsies of parietal peritoneum from the front abdominal wall were collected from 5 healthy rabbits (2 male and 3 female) and 8 persons (2 males and 6 females) mean age 52,50 ± 5,18 years. Semi-thin sections were fixed in Sorensen's phosphate buffer and stained with toluidin blue for light microscopy with Opton Photomicroskope III. Ultrathin sections for transmission electron microscopy were fixed in glutaraldehyde, postfixed in osmium tetroxyde, contrasted with uranyl acetate and viewed with EM Philips M208S transmission electron microscope. Normal rabbit and human parietal peritoneum is composed of a sheet of flat mesothelial cells, separated by a continuous basement membrane of connective tissue containing collagen and elastin fibers, fibroblasts, mononuclear phagocytes, lymphocytes, adipose tissue, small blood vessels, lymphatic vessels and nerves. Only continuous capillaries were observed. Preponderance of euchromatin over heterochromatin was found in the nuclei of endothelial cells. Endothelial citoplasm shows prominent rough endoplasmic reticulum, well-developed Golgi apparatus, numerous mitochondria and ribosomes. Numerous pinocytotic vesicles were found free within the cytoplasm or forming transendothelial channels. The peritoneal structure is similar in humans, rabbits and other rodents making them suitable models for research on peritoneal morphology and physiology.