title: Effect of angiotensin II type 1 receptor blocker on osteoporotic rat femurs.
abstract: BACKGROUND
  Osteoblasts and osteoclasts are known to express Ang II type I (AT1) receptor in cell cultures, suggesting the existence of local renin-angiotensin system (RAS) in bone. This study was designed to investigate the effects of losartan as AT1 receptor blocker on ovariectomized rats' femur.
  
  
  METHODS
  Losartan (5 mg/kg/day) was administered via oral gavage for 8 weeks. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, while tensile and three-point bending tests were performed for evaluation of biomechanical properties of bone. The trabecular porosity was analyzed by scanning electron microscopy.
  
  
  RESULTS
  There was a significant decrease in BMD values of ovariectomized rats' femurs which were reversed by losartan treatment. According to tensile test results, ultimate tensile strength and strain values of losartan treated ovariectomized rats' femurs increased and decreased, respectively, when compared to that of ovariectomized animals. Losartan treatment also caused a significant recovery in flexural strength and modulus parameters regarding respective control values, which mean losartan treated ovariectomized rats' femur had more force tolerance until break than ovariectomized rats' femur. Quantitative microscopic analysis showed larger trabecular porosity in ovariectomized rats than control rat femurs and it was significantly decreased after losartan treatment.
  
  
  CONCLUSIONS
  Blockage of AT1 receptor increased strength, mass and trabecular connections of ovariectomized rat femurs. Therefore, it is tempting to speculate that drugs, including AT1 receptor blockers, may be used for the treatment of osteoporosis or reduction of its detrimental effects in the future.
authors.affiliation: Department of Nutrition and Dietetics, Akdeniz University, Antalya, Turkey. barisozgurdonmez@hotmail.com
authors.forename: Baris Ozgur
authors.initials: BO
authors.lastname: Donmez
authors.forename: Semir
authors.initials: S
authors.lastname: Ozdemir
authors.forename: Mehmet
authors.initials: M
authors.lastname: Sarikanat
authors.forename: Nazmi
authors.initials: N
authors.lastname: Yaras
authors.forename: Pínar
authors.initials: P
authors.lastname: Koc
authors.forename: Necdet
authors.initials: N
authors.lastname: Demir
authors.forename: Binnur
authors.initials: B
authors.lastname: Karayalcin
authors.forename: Nurettin
authors.initials: N
authors.lastname: Oguz
mesh_terms: D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D005260:Female; D005269:Femur / Q000187:drug effects* / Q000473:pathology; D019808:Losartan / Q000494:pharmacology*; D010024:Osteoporosis / Q000188:drug therapy* / Q000473:pathology; D010052:Ovariectomy / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects; D013718:Tensile Strength / Q000187:drug effects
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D044140:Receptor, Angiotensin, Type 1; D019808:Losartan