Effects of amlodipine on bone metabolism in male albino Wistar rats

摘要

Amlodipine (dihydropyridine-type calcium channel blocker) is a widely used agent for the treatment of hypertension in human and veterinary medicine but detailed information about its effects on bone metabolism are missing. Therefore, the aim of our study was to investigate the effect of amlodipine on bone metabolism in male albino Wistar rats. Amlodipine (0.3 mg/100 g body weight; gavage) was administered to 8 rats for 8 weeks. Control group (n = 8) received aqua pro inj. (0.2 ml/100 g body weight; gavage). Bone marker concentrations of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I) and aminoterminal propeptide of procollagen type I in serum, and of bone alkaline phosphatase (BALP) in both serum and bone homogenate were measured by enzyme immunoassay. We investigated the expression of bone morphogenetic protein 2 (BMP-2) in proximal tibia using Western blotting, and bone mineral density was measured by Dual-energy X-ray Absorptiometry in lumbar and caudal vertebrae and in femoral areas. Mechanical properties of the femurs were measured by three-point bending of the shaft and compression testing of the femoral neck. After 8 weeks of amlodipine administration there was a significant decrease in serum concentrations of BALP (p = 0.0009) and CTX-I (p = 0.003), and the content of BALP in bone homogenate (p = 0.026) compared to the control. In addition, Western blot analysis indicated increased BMP-2 protein concentration after amlodipine administration. Our findings suggest that amlodipine has a retarding influence on bone metabolism in rats by decreasing bone turnover, which probably in consequence increases expression of BMP-2.