Effects Of Clenbuterol & Propranolol On Bone Metabolism In Ovariectomized Rats

Objective:To study effects of Clenbuterol and Propranolol on bone metabolism in ovariectomized rats.Methods: Forty-eight two-month-age female rats were divided equally into six groups, three groups are under ovariectomized,and the other three groups are under sham operated. After three months, two ovariectomized groups and two unovariectomized groups are givenβ-adrenergic receptor blocker propranolol andβ-adrenergic receptor agonist clenbuterol by the method of intraperitoneal injection lasting three months. Then the bone density of the femur and the lumbar vertebra were measured with the bone density gauge and the concentration of the osteocalcin in the rats'blood serum was detected by the method of ELISA. After sacrificed,specimens of the tibias were obtained and observed pathologically with HE staining ,later histomorphology analysis is taken.Results:The percentage of bone trabeculae area decreased 63.5% after the rats were ovariectomized ;the thickness of bone trabeculae decreased 28.9%;the bone density of the femur decreased 12.6%;The bone density of the lumbar vertebra reduced 11.1% ;the concentration of the osteocalcin in ovariectomized rats increased 41.5%. The percentage of bone trabeculae area decreased 13.2% with the use of Clenbuterol in the no-ovariectomize rats, and the thickness of bone trabeculae decreased 22.1% .The thickness of bone trabeculae decreased 11.8% with the use of Clenbuterol in the no-ovariectomize rats,and the thickness of bone trabeculae decrease 15.5% in the ovariectomized rats. The bone density of the femur decreased 13.9% with the use of Clenbuterol in the no-ovariectomize rats, and decreased 7.0% in the ovariectomized rats. The bone density of the lumbar vertebra decreased 8.8% with the use of Clenbuterol in the no-ovariectomize rats, but the bone density did not decrease in the ovariectomized rats. The concentration of the osteocalcin increased 4.5% with the use of Clenbuterol in the ovariectomized rats, but did not increased in the no-ovariectomize rats. The percentage of bone trabeculae area increased 8.8% with the use of Propranolol in the no-ovariectomize rats, and thickness of bone trabeculae increased 31.6%. The thickness of bone trabeculae increased 3.4% with the use of Propranolol in the no-ovariectomize rats and 20.3% in the ovariectomized rats. The bone density of the femur increased 11.7% with the use of Propranolol in the no-ovariectomize rats, and 6.0% in the ovariectomized rats.The bone density of the lumbar vertebra increased 6.0% with the use of Propranolol in the ovariectomized rats, and increased 4.4% in the no-ovariectomize rats. The concentration of the osteocalcin decreased 2.2% with the use of Propranolol, but did not decrease in the no-ovariectomize rats .Conclusions:①Theβ2AdR–agonist Clenbuterol can decrease the percentage of bone trabeculae area in the ovariectomized rats ;②Theβ2AdR–agonist Clenbuterol can decrease the bone density of the femur and the lumbar vertebra and can increase the concentration of the osteocalcin in the ovariectomized rats;③TheβAdR -blocker Propranolol can increase the percentage of bone trabeculae area and the thickness of bone trabeculae in the ovariectomized rats ;④TheβAdR -blocker Propranolol can increase the bone density of the femoral and the lumbar vertebra ,but can decrease the concentration of the osteocalcin in the ovariectomized rats .