Protective effect of atorvastatin on bone tissue in orchidectomised male albino Wistar rats

Comparative impact of systemic delivery of atorvastatin, simvastatin, and lovastatin on bone mineral density of the ovariectomized rats

PURPOSE

In addition to lipid-lowering properties, statins have been suggested to affect bone turnover by increasing the osteoblastic bone formation and blocking the osteoclastogenesis. However, there are many controversial reports regarding the beneficial effect of statins on osteoporosis. In this study, we investigated the therapeutic effects of the most important lipophilic statins administered orally for 60 days to the ovariectomized (OVX) female Sprague-Dawley rats and compared the effects on different harvested trabecular and compact bones.

METHODS

Thirty female rats were divided into five equal groups including the normal rats, untreated OVX rats (negative control), and the OVX rats treated with atorvastatin (20 mg/kg/day), simvastatin (25 mg/kg/day), and lovastatin (20 mg/kg/day). The osteoporotic animals were treated daily for 60 days and euthanized at the end of experiments. The effectiveness of these treatments was evaluated by biomechanical testing, histopathologic, histomorphometric, micro-CT scan, real-time PCR, and serum biochemical analysis. Moreover, the hepatotoxicity and rhabdomyolysis related with these treatments were assessed by biochemistry analysis and histopathological evaluation.

RESULTS

The results and statistical analysis showed that systemic delivery of simvastatin and lovastatin significantly increased serum calcium level, expression of osteogenic genes, bone mineral density (BMD), and biomechanical properties in comparison to the untreated OVX rats, especially in trabecular bones (P < 0.05). The results of different analysis also indicated that there was no statistical difference between the atorvastatin-treated animals and the negative control. Among all treatments, only atorvastatin showed an evident hepatotoxicity and myopathy.

CONCLUSIONS

It was concluded that the lovastatin and simvastatin efficiently ameliorated the OVX-induced osteoporosis. Moreover, the simvastatin-treated animals showed more resemblance to the normal group in terms of BMD, expression of osteogenic genes, serum biochemical parameters, histomorphometric findings, and biomechanical performance with no significant side-effects.

Changes in Bone Metabolism in Young Castrated Male Rats

PURPOSE

To determine the window of time during which osteoporosis affects the management of spinal surgery and the mechanism of bone metabolism changes in males with osteoporosis by examining changes in bone metabolism in young castrated male rats.

MATERIALS AND METHODS

A total of 30 Sprague-Dawley rats were randomly allocated into two study groups. Group 1 (control) received a sham surgery and Group 2 received bilateral orchiectomy to change bone mineral density (BMD). Serum osteocalcin, alkaline phosphatase (ALP), and collagen type 1 cross-linked C-telopeptide (CTX) were analyzed at postoperative date (POD) 8, 10, and 12 weeks. BMDs were measured using micro computed tomography scans.

RESULTS

Femoral and lumbar BMDs were decreased in the orchiectomy groups. BMDs in the sham and orchiectomy groups showed statistically differences at POD 8, 10, and 12 weeks for the femur (p=0.032, 0.008, 0.008) and lumbar spine (p=0.151, 0.008, 0.008, respectively). Serum osteocalcin, ALP, and CTX decreased gradually; however, N-terminal type 1 procollagen (P1NP) showed a slight increase yet no significant change.

CONCLUSION

In young castrated male rats, a significant decrease in BMD was observed after orchiectomy due to the mixture of two detrimental factors. Young castrated male rats did not reach peak BMD. Increased bone turnover causes bone resorption to exceed bone formation. This study may contribute to the creation of a valuable model for studies of male osteoporosis and the spinal surgery field.

L-Carnitine, but not coenzyme Q10, enhances the anti-osteoporotic effect of atorvastatin in ovariectomized rats

OBJECTIVE

Statins' therapy in osteoporosis can aggravate muscle damage. This study was designed to assess which agent, L-carnitine or coenzyme Q10, could enhance the anti-osteoporotic effect of atorvastatin while antagonizing myopathy in ovariectomized rats.

METHODS

Forty-eight female Sprague Dawley rats were used; forty rats were ovariectomized while eight were sham-operated. Eight weeks post-ovariectomy, rats were divided into ovariectomized-untreated group and four ovariectomized-treated groups (n=8) which received by gavage (mg/(kg∙d), for 8 weeks) 17β-estradiol (0.1), atorvastatin (50), atorvastatin (50)+L-carnitine (100), or atorvastatin (50)+coenzyme Q10 (20). At the end of therapy, bone mineral density (BMD), bone mineral content (BMC), and serum levels of bone metabolic markers (BMMs) and creatine kinase (CK) were measured. Femurs were used for studying the breaking strength and histopathological changes.

RESULTS

Treatment with atorvastatin+L-carnitine restored BMD, BMC, and bone strength to near normal levels. Estrogen therapy restored BMD and BMC to near normal levels, but failed to increase bone strength. Although atorvastatin and atorvastatin+coenzyme Q10 improved BMD, BMC, and bone strength, they failed to restore levels to normal. All treatments decreased BMMs and improved histopathological changes maximally with atorvastatin+L-carnitine which restored levels to near normal. Atorvastatin aggravated the ovariectomy-induced increase in CK level while estrogen, atorvastatin+L-carnitine, and atorvastatin+coenzyme Q10 decreased its level mainly with atorvastatin+L-carnitine which restored the level to near normal.

CONCLUSIONS

Co-administration of L-carnitine, but not coenzyme Q10, enhances the anti-osteoporotic effect of atorvastatin while antagonizing myopathy in ovariectomized rats. This could be valuable in treatment of osteoporotic patients. However, further confirmatory studies are needed.

Bone mineral density is reduced by telmisartan in male spontaneously hypertensive rats

BACKGROUND

Telmisartan, an angiotensin AT1 receptor blocker, and treadmill running were compared for their effects on bone mineral density (BMD) and biomechanical properties of male spontaneously hypertensive rats (SHR). It was hypothesized that running (18m/min/60min/d) and telmisartan (5mg/kg/d) would have a positive effect on bone parameters.

METHODS

Three-month-old male SHRs were divided into three groups: sedentary (S), telmisartan (T), and exercise (E). At the end of an 8-week protocol, femur and lumbar vertebrae were analyzed by dual-energy X-ray absorptiometry (DXA) for bone mineral density and by the three-point bending test for biomechanical properties. Blood pressure in all groups was measured by a tail-cuff manometer.

RESULTS

Telmisartan and treadmill running reduced blood pressure when compared to the sedentary group; however, telmisartan did not improve bone characteristics. Instead, it reduced BMD of femur total and lumbar vertebrae and worsened bone biomechanic properties. Treadmill running maintained bone characteristics and hence was effective in maintaining bone health.

CONCLUSION

Results showed that telmisartan negatively affected bones suggesting that caution should be taken in possible therapeutic applications for protecting bone health in hypertensive conditions. More studies are necessary to clarify the mechanisms through which telmisartan favors bone loss in this model.

Bone Mineral Density Changes after Orchiectomy using a Scrotal Approach in Rats

Objective

To investigate a suitable animal model for studies of male osteoporosis. Osteoporosis has a particularly high incidence in postmenopausal women, resulting in a substantial amount of research with respect to this disease in women. However, research on osteoporosis in men is still lacking.

Methods

Twenty 10-week-old male Sprague Dawley rats were used in this study, including 4 rats used to establish a baseline bone mineral density (BMD). The other 16 rats were divided into two groups: a sham surgery group (n=8), which underwent a sham operation, and an orchiectomized rat group (OCX) (n=8), which underwent bilateral OCX at 10 weeks of age. Bone mineral density was measured in 4 rats from both the sham surgery group and the OCX group 8 weeks after the surgery, while BMD in the remainder of the rats was measured 10 weeks post-surgery.

Results

Femoral BMD at 8 weeks post-surgery was found to be significantly lower in the OCX group compared to the sham group; a finding that was also similar 10 weeks post-surgery.

Conclusion

8 weeks after undergoing orchiectomy performed via a scrotal, white rats are a suitable model for studies of male osteoporosis.

Statins, bone metabolism and treatment of bone catabolic diseases

The discovery that statins had bone anabolic properties initiated many investigations into their use for treatment of bone catabolic diseases, such as osteoporosis. This paper reviews the molecular basis of statin's role in bone metabolism, and animal and human studies on the impact of systemic statins on osteoporosis-induced bone fracture incidence and healing, and on bone density. Limitations of systemic statins are described along with alternative dosing strategies, including local applications and bone-targeting systemic preparations. The principal findings of this review are: (1) traditional oral dosing with statins results in minimal efficacy in the treatment of osteoporosis; (2) local applications of statins show promise in the treatment of accessible bony defects, such as periodontitis; and (3) systemically administered statins which can target bone or inflammation near bone may be the safest and most effective strategy in the treatment of osseous deficiencies.