Ultrastructural localization of atrial natriuretic peptide-synthesizing cells in rat stomach / 中国组织工程研究

ABSTRACT

BACKGROUND: Atrial natriuretic peptide (ANP)-synthesizing cells distribute in all over the body. However, very little is known about the morphological localization and the distribution characteristics of ANP-synthesizing cells in different regions of rat stomach. OBJECTIVE: To investigate the ultrastructural localization and distribution characteristics of ANP-synthesizing cells in rat stomach. DESIGN: Repeated measurement experiment. SETTING: Chengde Medical Collage, Chengde, Hebei Province, China. MATERIALS This study was performed at the Laboratory for Institute of Chinese Materia Medica Immunology (provincial key laboratory), Chengde Medical College between October 2004 and July 2007. Eighteen adult Wistar rats of either gender, weighing 175-300 g, were provided by the Laboratory Animal Center of Chengde Medical College. The disposal of animals was conducted in accordance with ethical guidelines for the use and care of animals. ANP antibody and serum (Santa Cruz Biotechnology, Inc, USA), Protein A-15 nm colloidal gold labeled (Sino-American Biotechnology Company, China), CMIAS image analysis system (Beijing University of Aeronautics and Astronautics, China) and JEM-1200EX transmission election microscope (Japan) were used in the study. METHODS: After gastric and right atrial tissues (as a positive control in immanohistochemical staining for ANP-synthesizing cells) were fleshly excised from anesthetized Wistar rats, the specimens were longitudinally harvested along rat gastric cardiac region, gastric fundic mucosa and gastric pyloric region. Gastric tissue was performed immunohistochemical staining (for positive control) together with right atrial tissue, to observe the distribution characteristics of ANP-synthesizing cells in different regions of rat gastric tissue, and to localize ANP-synthesizing cells. The ultrastructural localization of ANP-synthesizing cells in the rat gastric mucosa was performed by postembedding immunoelectron microscopy. The area-density percentage of ANP-synthesizing cells in the different regions of rat stomach (gastric cardiac region, pyloric region and fundic region) was calculated with a CMIAS image analysis system. MAIN OUTCOME MEASURES: Morphological appearance and localization of ANP-synthesizing cells as well as the different area-density percentage in different regions of rat stomach. RESULTS: As a positive control, ANP-synthesizing cells showed intense positive expression in atrial myocytes and cytoplasm and in gastric mucosa (mainly within the lower third of rat gastric mucosa). The morphological appearance of the individual ANP-synthesizing cell was variable, exhibiting round, pyramidal and flask shapes. Negative staining for ANP-synthesizing cells was detected in the lamina propria, submucosa, and smooth muscle. ANP-synthesizing cells existed in different regions of rat stomach and its area-density was the largest in the pyloric region. The distribution order of ANP-synthesizing cells in area-density was gastric cardiac region > gastric pyloric region > gastric fundic mucosa in mucosa layer. CONCLUSION: ANP-synthesizing cells mainly exist within the lower third of the rat gastric mucosa. The percentage of area-density of ANP-synthesizing cellswas variable in different regions of rat gastric mucosa, and its percentage of area-density was the largest in the gastric cardiac region.