The present study examined the dose-dependent effect of vitamin E in reversing bone loss in ovariectomized (Ovx) rats. Sprague-Dawley rats were either Sham-operated (Sham) or Ovx and fed control diet for 120 days to lose bone. Subsequently, rats were divided into 5 groups (n = 12/group): Sham, Ovx-control, low dose (Ovx + 300 mg/kg diet; LD), medium dose (Ovx + 525 mg/kg diet; MD), and high dose (Ovx + 750 mg/kg diet; HD) of vitamin E and sacrificed after 100 days. Animals receiving MD and HD of vitamin E had increased serum alkaline phosphatase compared to the Ovx-control group. Bone histomorphometry analysis indicated a decrease in bone resorption as well as increased bone formation and mineralization in the Ovx groups supplemented with MD and HD of vitamin E. Microcomputed tomography findings indicated no effects of vitamin E on trabecular bone of fifth lumbar vertebrae. Animals receiving HD of vitamin E had enhanced fourth lumbar vertebra quality as evidenced by improved ultimate and yield load and stress when compared to Ovx-control group. These findings demonstrate that vitamin E improves bone quality, attenuates bone resorption, and enhances the rate of bone formation while being unable to restore bone density and trabecular bone structure.

Rats fed gestational diets high in multivitamin or folate produce offspring of altered phenotypes. We hypothesized that female rat offspring born to dams fed a gestational diet high in folic acid (HFol) have compromised bone health and that feeding the offspring the same HFol diet attenuates these effects. Pregnant rats were fed diets with either recommended folic acid (RFol) or 10-fold higher folic acid (HFol) amounts. Female offspring were weaned to either the RFol or HFol diet for 17 weeks. HFol maternal diet resulted in lower offspring body weights (6%, P = 0.03) and, after adjusting for body weight and femoral length, smaller femoral area (2%, P = 0.03), compared to control diet. After adjustments, HFol pup diet resulted in lower mineral content (7%, P = 0.01) and density (4%, P = 0.002) of lumbar vertebra 4 without differences in strength. An interaction between folate content of the dam and pup diets revealed that a mismatch resulted in lower femoral peak load strength (P = 0.01) and stiffness (P = 0.002). However, the match in folate content failed to prevent lower weight gain. In conclusion, HFol diets fed to rat dams and their offspring affect area and strength of femurs and mineral quantity but not strength of lumbar vertebrae in the offspring.

Osteoporosis represents an imbalance between bone formation and bone resorption. As a result of low estrogen levels, it is markedly prevalent during menopause, thus making such patients susceptible to fractures. Both bone formation and resorption are modulated by nitric oxide (NO). Currently, there are no risk-free pharmaceutical prevention therapies for osteoporosis. COMB-4, a nutraceutical combination of Paullinia cupana, Muira puama, ginger, and L-citrulline, known to activate the NO-cGMP pathway, was reported to accelerate fracture healing in the rat. To determine whether COMB-4 could be effective in preventing menopausal osteoporosis, it was compared to estradiol (E2) in an ovariectomized (OVX) rat osteoporosis model. Nine-month-old female Sprague Dawley rats were divided into SHAM, OVX, OVX+E2, and OVX+COMB-4. After 100 days of treatment, bone mineral density (BMD) and bone mineral content (BMC) were measured by DXA scan. TRAP staining was performed in the femur and lumbar vertebrae. TRACP 5b and osteocalcin levels were assayed in the serum. MC3T3-E1 cells were differentiated into osteoblasts and treated with COMB-4 for one week in order to evaluate calcium deposition by Alizarin staining, cGMP production by ELISA, and upregulation of the nitric oxide synthase (NOS) enzymes by RT-PCR. OVX resulted in a decrease in BMD, BMC, and serum osteocalcin and an increase in serum TRACP 5b. Except for an increase in BMC with COMB-4, both E2 and COMB-4 reverted all bone and serum markers, as well as the number of osteoclasts in the vertebrae, to SHAM levels. Incubation of MC3T3-E1 cells with COMB-4 demonstrated an increase in the three NOS isoforms, cGMP, and calcium deposition. COMB-4 increased BMD in OVX rats by inhibiting bone resorption and increasing calcium deposition presumably via activation of the NO-cGMP pathway. It remains to be determined whether COMB-4 could be a potential nutraceutical therapy for the prevention of premenopausal bone loss.