Endocrine Abstracts

Objective: HMG Coenzyme A reductase inhibitors (statins) mainly decrease low-density lipoproteins (LDL) cholesterol but also have been found to have beneficial effects in the skeleton. The aim of this study was to examine atorvastatin effects in vivo on femoral and vertebral bone strength.

Methods: An ovariectomized (OVX), a glucocorticoid induced osteoporotic (GIO) and an OVX plus GIO group of rat models were used to study the effects of atorvastatin. Sprague-Dawley rats were OVX at 120-140 days of age. Experimental group included: (1) OVX + Atorvastatin, (2) OVX and /or glucocorticoid induced osteoporosis control (OSTEOPOROSIS GROUP) and (3) Sham OVX. Treatment was initiated 12 weeks after ovariectomy. Atorvastatin (5 mg/kg/day) and vehicle treatment were administered by gavage for 6 weeks. Then the rats were sacrificed. The effects of OVX, atorvastatin treatment, and maintenance regimens were measured at femur and lumbal vertebras (L4). Bone strength was assessed with compression test in vertebras and with three-point bending test in femurs by using Shimadzu AG-50 kNG as newton (N). Bone mineral densities of these rats were assessed before and after treatment with Hologic QDR 4500 A, by small animal software. Statistical analyses were made by Mann Whitney-U nonparametric test, correlation analysis and Kruskal Wallis test.

Results: It was shown that atorvastatin increases femoral and vertebral bone strength significantly in osteoporotic rats. While bone strength was found to be 86.35 ± 18.3 N in femurs of OVX plus atorvastatin and 73.44 ± 16.47 in femurs of the osteoporotic group (p=0,019) whereas 172.47 ± 37.67 N in vertebras of the OVX plus atorvastatin group and 107.46 ± 27.89 N in vertebras of the osteoporosis group (p= 0.000). We have found a medium degree correlation between the values of femoral and vertebral bone density and femoral and vertebral bone strength.

Conclusion: In this study, The use of atorvastatin at dosage 5 mg/kg/day was associated with the increase of femoral and vertebral bone strength significantly in Sprague-Dawley rats.