Effect of Blocking L-Type Calcium Channels on Bone in Ovariectomy Model of Osteoporosis in Rats, MOUSTAFA H. ABDEL SALAM
Abstract
Background: Calcium channel blockers are widely used in many cardiovascular diseases. These diseases are common in old age persons suffering from osteoporosis. However, the impact of calcium channel blockade on osteoporosis is still controversial. This study investigated effect of calcium channel blockers on bone metabolism in an ovarictomized rat model of osteoporosis.
Methods: 50 female white albino rats were divided into 5 equal groups: Sham operated control, ovariectomized, Ovariectomized + Diltiazem treatment, Ovariectomized + Verapamil treatment and Ovariectomized + Amlodipine treat-ment groups. At the end of the experiment, femora were examined for length, dry weight wet weight, ash weight calcium and phosphate levels. Serum concentrations of calci-um, phosphate, osteocalcin (BGP), Carboxy-terminal collagen crosslinks (CTX) and alkaline phosphatase activity (ALP) were measured.
Results: In ovarictomized rats, treatment for eight weeks with Diltiazem, Verapamil or Amlodipine calcium channel blockers induced a significant increase in bone-dry weight, ash weight and bone calcium content reflecting an increase in bone density and mineral content when compared with control groups. They also significantly decreased serum concentrations of calcium, phosphate, osteocalcin, carboxy-terminal collagen crosslinks and alkaline phosphatase. How-ever, amlodipine treated animals had significantly lower bone-dry weight, ash weight and bone calcium content and signif-icantly higher serum concentrations of calcium, phosphate, osteocalcin, carboxy-terminal collagen crosslinks and alkaline phosphatase when compared with the other two CCB groups.
Conclusion: All the examined types of calcium channel blockers have possible beneficial effects in osteoporotic animals. The benzothiazepine (Diltiazem) and phenylalky-lamines (verapamil) subtypes of calcium channel blockers induced a significant improvement in all bone markers. The dihydropyridine (Amlodipine) subtype had similar protective effect however, it was significantly lower than the other two CCBs.