title: The effects of water immersion and restraint stress on the expressions of apelin, apelin receptor (APJR) and apoptosis rate in the rat heart.
abstract: Apelin has been identified as an endogenous ligand of the orphan G-protein-coupled apelin receptor (APJR). These receptors are widely expressed in the central nervous system and periphery and play a role in the regulation of fluid and glucose homeostasis, feeding behavior, vessel formation, cell proliferation and immunity. We aimed to investigate whether water immersion and restraint stress have effects on apelin and APJR expression and apoptosis in heart tissue of male Wistar rats. The cardiac tissues were obtained from control, water immersion and restraint stress (WIRS) and apelin antagonist (F13A)+WIRS groups of rats and embedded in paraffin wax. Immunohistochemical staining methods were used to localize apelin, APJR and TUNEL immunopositive cells. H-SCORE was used for semi-quantitative determinations. Apelin protein levels were determined by Western blot in the cardiac tissues and plasma corticosteroid levels were measured by enzyme immunoassay (EIA). Apelin immunolocalization was found especially in endothelial cells and mast cells and faintly in cardiomyocytes, APJR immunostaining was shown in endothelial cells and cardiomyocytes, and TUNEL reaction was observed in endothelial cells and in some fibroblasts. Apelin expression was significantly increased in the WIRS and F13A+WIRS groups compared to the control group. The APJR reaction was similar in all groups. The number of TUNEL-positive cells was significantly higher in the F13A+WIRS group than that of the control group. Our study showed that WIRS for 6h increased plasma corticosterone levels and cardiac apelin expression in rats. The increased levels of apelin inhibited stress-induced apoptosis in heart. These results may be important for the therapeutic approach to a variety of stress-related heart disease.
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey. Electronic address: iustunel@akdeniz.edu.tr.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ustunel
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Nuray
authors.initials: N
authors.lastname: Acar
authors.affiliation: Department of Physiology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Burcu
authors.initials: B
authors.lastname: Gemici
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Ozbey
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Imren
authors.initials: I
authors.lastname: Edizer
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Soylu
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Tepekoy
authors.affiliation: Department of Physiology, Akdeniz University, Faculty of Medicine, 07070 Campus, Antalya, Turkey.
authors.forename: Vecihe Nimet
authors.initials: VN
authors.lastname: Izgut-Uysal
mesh_terms: D000818:Animals; D000073861:Apelin; D000075244:Apelin Receptors; D017209:Apoptosis; D015153:Blotting, Western; D003345:Corticosterone / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006321:Heart / Q000503:physiopathology*; D007101:Immersion; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D015701:Near Drowning; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000503:physiopathology*
chemical_list: D000073861:Apelin; D000075244:Apelin Receptors; C498579:Apln protein, rat; C491285:Aplnr protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D043562:Receptors, G-Protein-Coupled; D003345:Corticosterone
keywords: APJR; Apelin; Apoptosis; F13A; Heart; Water-immersion and restraint stress