title: The effect of immunosuppression on aortic dilatation in a rat aneurysm model.
abstract: This study was conducted to investigate whether systemic immunosuppression attenuated aortic dilatation in a rat aneurysm model. Sprague-Dawley rats were subjected to elastase infusion of the infrarenal aorta and divided into two groups of 12 rats each. The immunosuppression group (group 1) was given subcutaneous injections of cyclosporine A (5 mg/kg per day), azathioprine (2 mg/kg per day), and methylprednisolone (2 mg/kg per day) from the operative day until postoperative day (POD) 6. An additional subcutaneus injection of cyclophosphamide 30 mg/kg was also given on the operative day. The control group (group 2) was given subcutaneous injections of saline. Relaparotomy was performed on POD 7. After measurement of the aortic diameter, aortography and ultrasonography were performed in three rats from each group, following which the aortas were excised for histologic examination. The aortic diameter was significantly smaller in group 1 (2.58 +/- 0.37 mm) than in group 2 (6.21 +/- 1.74 mm) (P < 0.01) and the aortic lumen was slightly dilated in group 1, whereas it was spherically dilated in group 2. Total loss of elastic tissue was seen in both groups. Inflammatory cell infiltration and collagen fiber fragmentation were noted in group 2, whereas very little inflammatory cell infiltration and well-preserved collagen fibers were seen in group 1. These findings showed that immunosuppression attenuates aortic dilatation, partly by preserving the collagen fibers, in this rat aneurysm model.
authors.affiliation: First Department of Surgery, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: M
authors.initials: M
authors.lastname: Yokokawa
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Higashide
authors.forename: Y
authors.initials: Y
authors.lastname: Katoh
authors.forename: S
authors.initials: S
authors.lastname: Sugiyama
authors.forename: T
authors.initials: T
authors.lastname: Misaki
mesh_terms: D000818:Animals; D001014:Aortic Aneurysm / Q000188:drug therapy* / Q000276:immunology; D003094:Collagen / Q000187:drug effects; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000494:pharmacology*; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology*; D004108:Dilatation, Pathologic; D004195:Disease Models, Animal; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D007279:Injections, Subcutaneous; D008297:Male; D010196:Pancreatic Elastase / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D003520:Cyclophosphamide; D003094:Collagen; D010196:Pancreatic Elastase