Osteopenia In Rats Research Articles

Metformin attenuates diabetes-induced osteopenia in rats is associated with down-regulation of the RAGE-JAK2-STAT1 signal axis.

Osteopenia and fragile fractures are diabetes-associated complications. Many hypoglycemic drugs have effects on bone metabolism. Metformin, as is a prescribed medication for type 2 diabetes mellitus (T2DM), had been reported to have osteoprotective effects beyond its hypoglycemic effect, however the potential mechanism behind these effects remains unclear. In this study, we aimed to investigate the comprehensive effects of metformin on bone metabolism in T2DM rat model and elucidate the potential mechanism. Goto-Kakizaki spontaneous T2DM rats with significant hyperglycemia were treated with/without metformin for 20 weeks. Glucose tolerance was tested and all rats were weighed every two weeks. The osteoprotective effects of metformin in diabetic rats were determined by quantifying serum bone biomarkers, μ-CT imaging, histological staining, bone histomorphometry, and biomechanical properties analyses. Potential targets of metformin in the treatment of T2DM and osteoporosis were predicted using network pharmacology. The effects of metformin on mesenchymal stem cells (C3H10) cultured in high glucose medium were evaluated by CCK-8 assay, alkaline phosphatase (ALP) staining, qPCR and western blotting. This study demonstrated that metformin significantly attenuated osteopenia, decreased serum glucose and glycated serum protein (GSP) levels, improved bone microarchitecture, and biomechanical properties in GK rats with T2DM. Metformin significantly increased biomarkers of bone formation, and significantly decreased muscle ubiquitin C (Ubc) expression. Network pharmacology analysis found that signal transducer and activator of transcription1 (STAT1) would be a potential target of metformin for regulating bone metabolism. Metformin increased C3H10​cell viability in vitro, alleviated ALP inhibition caused by hyperglycemia, increased the osteogenic gene expression of runt-related transcription factor 2 (RUNX2), collagen type I alpha 1 (Col1a1), osteocalcin (OCN), and ALP, while suppressing RAGE and STAT1 expression. Metformin also increased the protein expression of Osterix and decreased that of RAGE, p-JAK2, and p-STAT1. Our results demonstrate that metformin attenuated osteopenia and improved bone microarchitecture in GK rats with T2DM and significantly promoted stem cell osteogenic differentiation under high glucose condition. The effects of metformin on bone metabolism are closely associated with the suppression of RAGE-JAK2-STAT1 signaling axis. Our research provides experiment evidence and potential mechanistic rationale for the use of metformin as an effective candidate for diabetes-induced osteopenia treatment.

Using X-ray diffraction in characterization of bone remodeling and nanocomposites in ovariectomized rats osteopenia model

Abstract Sedentary lifestyle and physiological menopause are among the risk factors of osteopenia, especially in elderly people. However, bone mineral density decrease can also be observed in young individuals, for instance, due to deficiency of female sex hormones after surgical interventions, particularly ovariectomy. Our research enabled us to assess the efficacy of whole-body vibration in preventing the loss of bone mineral density in the ovariectomy rat osteopenia model. Thus, whole-body vibration with acceleration level 0.3 g and frequency 50 Hz was used on young female rats, which had been subjected to ovariectomy (n = 18). It had been conducted for 24 weeks, exposure time – 30 minutes per day, 5 times a week. Assessment of mineral component loss of the tibia was performed by means of X-ray diffraction. Bone remodeling was assessed by determining hormones: parathyroid hormone and calcitonin, Ca and P in the blood. X-ray diffraction is an effective method, which enables the evaluation a nanocomposites structure of the bone tissue in the experiment. In the article, we applied this method to determine the loss of bone mineral mass after ovariectomy and the impact of whole-body vibration under such conditions. In the ovariectomy group, the volume of a mineral component significantly decreased starting already from the 16th week (р<0.05) versus control. However, in the group with ovariectomy + whole-body vibration, the loss of a mineral component was insignificant during 8-16 weeks of the investigation, compared with the control group. On the 24th day, the spectrums almost did not differ from ovariectomized rats group. Meanwhile, hormone levels changed in ovariectomized rats group. It should be emphasized that the aforementioned whole-body vibration parameters do not cause severe bone damage or further negative consequences.

The bone alterations in hind limb amputation rats in vivo

Osteoporosis, which is characterized by bone loss, increases the risk of fractures and s and seriously affected the amputee’s health. Muscle mass is an important factor affecting bone mineral density (BMD). Muscular atrophy and decreased muscle mass can cause BMD to fall. The bone quantity and quality are used to assess by Microcomputer tomography (micro-CT) with non-destructive. To investigate the performance of micro-CT in evaluating amputation-induced osteopenia in rats, the micro-CT was used to evaluate the change of the microstructure in trabecular bone and cortical bone of amputation. Muscle morphology was analyzed by micro-CT and transmission electron microscopy. Female Sprague–Dawley rats (8 week old) were divided into two groups: control (CON) groups and left hind limb amputation (LHLA). At 35 days, microstructure and volumetric bone mineral density (vBMD) of the tibia and femur were detected through micro-CT. The results showed: (1) the trabecular and cortical vBMD of the proximal tibia and distal femur in the LHLA group were significantly lower than those in the CON group. (2) Compared with the CON group, the trabecular number, bone volume fraction and trabecular thickness of proximal tibia and distal femur in LHLA group decreased significantly, whereas the trabecular separation, structure model index and bone surface/bone volume increased significantly in LHLA group. (3) The whole cross-sectional area (CSA) of whole calf muscles of left limb in LHLA group decreased significantly compared with CON group. In general, hind limb amputation could cause bone loss, changes in the microstructure of trabecular bone and muscle atrophy. Micro-CT is sensitive in evaluating bone microstructure destruction caused by amputation, and can be used for early diagnosis or monitor the development of bone loss in amputation in vivo.

A butanolic fraction from the standardized stem extract of Cassia occidentalis L delivered by a self-emulsifying drug delivery system protects rats from glucocorticoid-induced osteopenia and muscle atrophy

We recently reported that a butanol soluble fraction from the stem of Cassia occidentalis (CSE-Bu) consisting of osteogenic compounds mitigated methylprednisone (MP)-induced osteopenia in rats, albeit failed to afford complete protection thus leaving a substantial scope for further improvement. To this aim, we prepared an oral formulation that was a lipid-based self-nano emulsifying drug delivery system (CSE-BuF). The globule size of CSE-BuF was in the range of 100–180 nm of diluted emulsion and the zeta potential was −28 mV. CSE-BuF enhanced the circulating levels of five osteogenic compounds compared to CSE-Bu. CSE-BuF (50 mg/kg) promoted bone regeneration at the osteotomy site and completely prevented MP-induced loss of bone mass and strength by concomitant osteogenic and anti-resorptive mechanisms. The MP-induced downregulations of miR29a (the positive regulator of the osteoblast transcription factor, Runx2) and miR17 and miR20a (the negative regulators of the osteoclastogenic cytokine RANKL) in bone was prevented by CSE-BuF. In addition, CSE-BuF protected rats from the MP-induced sarcopenia and/or muscle atrophy by downregulating the skeletal muscle atrogenes, adverse changes in body weight and composition. CSE-BuF did not impact the anti-inflammatory effect of MP. Our preclinical study established CSE-BuF as a prophylactic agent against MP-induced osteopenia and muscle atrophy.

Effect of bisphosphonate on temporomandibular joint in osteopenia-induced rats by botulinum toxin A injection on masticatory muscle: a preliminary study

BackgroundBotulinum toxin injection on the masticatory muscle induces the osteopenic condition on the ipsilateral condyle. Bisphosphonate suppresses bone resorption and is used to treat osteopenic or osteoporotic condition. This study aimed to evaluate the effect of bisphosphonate administration on prevention of condylar resorption and botulinum toxin A-induced disuse osteopenia in rats.ResultsThe volume of the condyle and bone volume/tissue volume (BV/TV, %) showed a strong tendency towards statistical significance (p = 0.052 and 0.058). Trabecular thickness (Tb.Th, mm) and trabecular number (Tb.N, 1/mm) were significantly smaller in the Botox group than in the other groups (p < 0.05). The volume of the condyle and BV/TV in the bisphosphonate 100 and bisphosphonate 200 groups showed similar values when compared with the control group.ConclusionBisphosphonate administration after botulinum toxin A injection in the masticatory muscles appears to prevent condyle resorption and botulinum toxin-induced disuse osteopenia in rats.

Retraction: Preventive effects of risedronate and calcitriol on cancellous osteopenia in rats treated with high-dose glucocorticoid.

The following articles have been retracted by the Editorial Board of Experimental Animals, because some parts of their contents were published elsewhere.

Effect of long-term administration of mangiferin from Belamcanda chinensis on bone metabolism in ovariectomized rats

Mangiferin has demonstrated in vitro inhibitory influence on RANKL (Receptor Activator of Nuclear Factor Kappa B Ligand) mediated osteoclasts activity. In this study we evaluated the effect of mangiferin on ovariectomy-induced osteopenia in rats. Animals were randomized into four groups: SHAM (“sham” operated group) and three ovariectomized groups (OVX-C – controls; OVX-M10 – mangiferin 10 mg/kg/day and OVX-M30 – mangiferin 30 mg/kg/day). Mangiferin administration began 3 months after ovariectomy and was continued for 6 consecutive months. In mangiferin-treated rats we demonstrated decrease in bCTX (beta C-terminated telopeptide of type I collagen) level and increase in BMD (bone mineral density) comparing to OVX-C. Bone histomorphometric parameters were in OVX-M10 and OVX-M30 significantly better than in OVX-C. No influence of mangiferin on OC (osteocalcin) level was detected. Thus mangiferin demonstrated antiresorptive influence on bone metabolism and it attenuated ovariectomy-induced bone changes.

Calcitonin-Loaded Thermosensitive Hydrogel for Long-Term Antiosteopenia Therapy.

Effective antiosteopenia therapy can be achieved by designing long-term protein/peptide drug delivery systems for bone trabecula restoration. Here we show that a complex of salmon calcitonin and oxidized calcium alginate (sCT-OCA) was prepared and loaded into a thermosensitive copolymer hydrogel for long-term antiosteopenia treatment. The triblock copolymer, poly(d,l-lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(d,l-lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) exhibited sol-gel transition at body temperature. The sustained release of sCT from the in situ gelling system was determined by both the degradation of the hydrogel and the decomposition of the sCT-OCA complex. This system showed sustained effects in reducing serum calcium and bone trabecula reconstruction in the treatment of glucocorticoid-induced osteopenia in rats for approximately 30 days after a single subcutaneous injection, which may shed light on antiosteopenia therapy in the future.

Jumping exercise preserves bone mineral density and mechanical properties in osteopenic ovariectomized rats even following established osteopenia.

The present study investigated the effects of jump training on bone structure before and after ovariectomy-induced osteopenia in 80 10-week-old Wistar rats. Forty rats (prevention program) were randomly allocated to one of four equal groups (n=10): sham-operated sedentary (SHAM-SEDp), ovariectomized (OVX) sedentary (OVX-SEDp), sham-operated exercised (SHAM-EXp), and OVX exercised (OVX-EXp). SHAM-EXp and OVX-EXp animals began training 3days after surgery. Another 40 rats (treatment program) were randomly allocated into another four groups (n=10): sham-operated sedentary (SHAM-SEDt), OVX sedentary (OVX-SEDt), sham-operated exercised (SHAM-EXt), and OVX exercised (OVX-EXt). SHAM-EXt and OVX-EXt animals began training 60days after surgery. The rats in the exercised groups jumped 20 times/day, 5days/week, to a height of 40cm for 12weeks. At the end of the experimental period, serum osteocalcin, follicle-stimulating hormone (FSH) dosage, dual X-ray absorptiometry (DXA), histomorphometry, and biomechanical tests were analyzed. The OVX groups showed higher values of FSH and body weight (p<0.05). DXA showed that jump training significantly increased bone mineral density of the femur and fifth lumbar vertebra (p<0.05). The stiffness of the left femur and fifth lumbar vertebra in the exercised groups was greater than that of the sedentary groups (p<0.05). Ovariectomy induced significant difference in bone volume (BV/TV, percent), trabecular separation (Tb.Sp, micrometer), and trabecular number (Tb.N, per millimeter) (p<0.05) compared to sham operation. Jump training in the OVX group induced significant differences in BV/TV, Tb.Sp, and Tb.N and decreased osteoblast number per bone perimeter (p<0.05) compared with OVX nontraining, in the prevention groups. Osteocalcin dosage showed higher values in the exercised groups (p<0.05). Jumping exercise induced favorable changes in bone mineral density, bone mechanical properties, and bone formation/resorption markers. Jump training is effective to prevent bone loss after ovariectomy even when osteopenia is already established.

CO01. Posttraumatic osteopenia in rats with different models of femur fractures

CO01. Posttraumatic osteopenia in rats with different models of femur fractures

Role of some Herbs in Improvement of Mineral Absorption, Control of Anemia and Osteopenia in Rats دور بعض الأعشاب فى تحسين امتصاص الأملاح المعدنية والتحکم فى أنيميا نقص الحديد فى الفئران

asfunctional food supplement to improve Ca, P, Mg and Fe absorption aswell as to prevent and treat both anemia and osteoporosis associatedwith deficiency in calcium and iron intake were evaluated in rats. Threeexperimental groups were fed diet supplemented with 10% tested herbsfor 4 wk versus the control rat group fed basal diet free in iron andcalcium. At the end of the experiment, rat groups fed herbssupplemented diets were characterized by significant dose-relatedincreases in the level of serum minerals Ca (2.1 ± 0.03 to 2.58 ± 0.01mmol/L), P (0.72 ± 0.3 to 0.93 ± 0.02 mmol/L), Mg (0.71 ± 0.01 to0.91 ± 0.01 mmol/L) and Fe (69.11 ± 4.55 to 84.3 ± 2.12 μg/dl). Inaddition, there were variable increases in the measured levels ofhemoglobin (11.11 ± 1.1 to 14.25 ± 1.1 g/L), hematocrit (39.15 ± 0.15to 42.15 ± 1.27 %) and ferritin (49.55 ± 2.25 to 65.12 ± 0.15 μg/dl) inherbs fed groups in a dose-dependent fashion compared with thecontrol group. These data suggested that Safforn

Antiosteoporotic activity of Du–Zhong–Wan water extract in ovariectomized rats

Context Eucommiae Cortex and Radix Dipsaci, occurring in a ratio of 1:1 in Du-Zhong-Wan (DZW), a Chinese herbal medicine, is available as a water extract followed by ethanol precipitation for the treatment of osteoporosis, fractures and menopausal syndrome.Objective This study investigates the protective effects of DZW in ovariectomy (OVX)-induced bone loss in a rat osteopenia model.Materials and methods Sixty Sprague–Dawley rats were randomly divided into the sham-operated group (SHAM) and five OVX subgroups: OVX with vehicle (OVX), 17β-estradiol (E2) and with three graded doses of DZW. Daily oral administration of the different samples started on the fifth week and lasted for 12 weeks, respectively. The body weight, uterus wet weight, serum biochemical parameters, bone mineral density (BMD), bone biomechanical properties, bone microarchitecture and immunohistochemistry were examined.Results Compared with the SHAM group, the DZW treatment significantly reversed the osteoporotic changes in OVX rats. The DZW-H group showed that serum tartrate-resistant acid phosphatase 5b (TRACP-5b) levels reduced by 152.25% (p < 0.01) and osteocalein (OCN) levels dose dependently increased by 118.43% (p < 0.01) as compared with the OVX group. Compared with the OVX group, the DZW at different three dosages of DZW evidently increased the right femur BMD by 112.43, 114.56 and 116.45%, and dramatically promoted bone quality and bone strength (p < 0.05). Further, immunohistochemical evaluation also showed that DZW administration increased ER expression in uteri (p < 0.01).Conclusions DZW exhibits an anti-osteoporotic effect, probably mediated via phyto-estrogenic effects. It might be a potential herbal alternative for the management of postmenopausal osteoporosis.

Effects of 8-Prenylnaringenin and Whole-Body Vibration Therapy on a Rat Model of Osteopenia.

Background. 8-Prenylnaringenin (8-PN) is the phytoestrogen with the highest affinity for estrogen receptor-α (ER-α), which is required to maintain BMD. The osteoprotective properties of 8-PN have been demonstrated previously in tibiae. We used a rat osteopenia model to perform the first investigation of 8-PN with whole-body vertical vibration (WBVV). Study Design. Ovariectomy was performed on 52 of 64 Sprague-Dawley rats. Five weeks after ovariectomy, one group received daily injections (sc) of 8-PN (1.77 mg/kg) for 10 weeks; a second group was treated with both 8-PN and WBVV (twice a day, 15 min, 35 Hz, amplitude 0.47 mm). Other groups received either only WBVV or no treatment. Methods. The rats were sacrificed 15 weeks after ovariectomy. Lumbar vertebrae and femora were removed for biomechanical and morphological assessment. Results. 8-PN at a cancer-safe dose did not cause fundamental improvements in osteoporotic bones. Treatment with 8-PN caused a slight increase in uterine wet weight. Combined therapy using WBVV and 8-PN showed no significant improvements in bone structure and biomechanical properties. Conclusion. We cannot confirm the osteoprotective effects of 8-PN at a cancer-safe dose in primary affected osteoporotic bones. Higher concentrations of 8-PN are not advisable for safety reasons. Adjunctive therapy with WBVV demonstrates no convincing effects on bones.

Effects of urocortin on spine?

SummaryUrocortin (UCN) is a member of the cortico tropin-releasing factor family. UCN enhances osteoblast differentiation and inhibits osteoclasts in vitro. In the present study, the effect of UCN on spine was assessed in the rat osteopenia model.Sprague Dawley rats (3 month old) were either ovariectomized (OVX, n = 48) or sham operated (n = 12). After 9 weeks, OVX rats were divided into 4 groups (n = 12): OVX, UCN low (3 µ/kg BW), UCN high (30 µ/kg BW), estradiol-17β-benzoate (0.2 mg/kg BW). UCN was administered daily s. c., estrogen was supplied with food for 35 d. Thereafter, the lumbar vertebral bodies were analyzed by biomechanical test, micro-CT, pQCT, gene expression and ashing analyses. Serum alkaline phosphatase (AP), beta-Crosslaps, calcium, leptin levels were assessed.Stiffness, BMD, BV/TV, trabecular parameters improved in UCN high group. UCN low dose had less effect on spine. AP was enhanced in UCN high group, leptin increased in both UCN groups, other serum parameters and expression of bone genes did not change. UCN high dose showed osteoprotective effect in spine.Further studies are needed to understand mechanism of UCN action on bone and to reveal potential side effects.

Additive effect of PTH (1–34) and zoledronate in the prevention of disuse osteopenia in rats

Immobilization is known to cause a rapid bone loss due to increased osteoclastic bone resorption and decreased osteoblastic bone formation. Zoledronate (Zln) is a potent anti-resorptive pharmaceutical, while intermittent PTH is a potent bone anabolic agent. The aim of the present study was to investigate whether PTH or Zln alone or in combination could prevent immobilization-induced osteopenia.Immobilization was achieved by injecting 4IU Botox (BTX) into the right hind limb musculature. Seventy-two 16-week-old female Wistar rats were randomized into 6 groups; baseline (Base), control (Ctrl), BTX, BTX+PTH, BTX+Zln, and BTX+PTH+Zln. PTH (1–34) (80μg/kg) was given 5days/week and Zln (100μg/kg) was given once at study start. The animals were killed after 4weeks of treatment. The bone properties were evaluated using DEXA, μCT, dynamic bone histomorphometry, and mechanical testing.BTX resulted in lower femoral trabecular bone volume fraction (BV/TV) (−25%, p<0.05), lower tibial trabecular bone formation rate (BFR/BS) (−29%, p<0.05), and lower bone strength (Fmax) at the distal femur (−19%, p<0.001) compared with Ctrl. BTX+PTH resulted in higher femoral BV/TV (+31%, p<0.05), higher tibial trabecular BFR/BS (+297%, p<0.05), and higher Fmax at the distal femur (+11%, p<0.05) compared with BTX. BTX+Zln resulted in higher femoral BV/TV (+36%, p<0.05), lower tibial trabecular BFR/BS (−93%, p<0.05), and higher Fmax at the distal femur (+10%, p<0.05) compared with BTX. BTX+PTH+Zln resulted in higher femoral BV/TV (+70%, p<0.001), higher tibial trabecular BFR/BS (+59%, p<0.05), and higher Fmax at the distal femur (+32%, p<0.001) compared with BTX.In conclusion, BTX-induced immobilization led to lower BV/TV, BFR/BS, and Fmax. In general, PTH or Zln alone prevented the BTX-induced osteopenia, whereas PTH and Zln given in combination not only prevented, but also increased BV/TV and BFR/BS, and maintained Fmax at the distal femoral metaphysis compared with Ctrl.

Effect of Urocortin on strength and microarchitecture of osteopenic rat femur

As yet there is no evidence of the potential antiosteoporotic effect of Urocortin-1 (UCN), a corticotropin releasing factor related peptide, in vivo. In this study, and for the first time, we investigated the effect of UCN in a rat osteopenia model. Sixty female Sprague-Dawley rats were divided into 5 groups: (1) sham-operated, (2) untreated ovariectomized (OVX) rats, (3) and (4) OVX animals treated for 5 weeks with daily subcutaneous low-dose UCN (3 μg/kg of BW) or high-dose UCN (30 μg/kg of BW) 8 weeks after ovariectomy, and (5) OVX rats treated with daily estrogen (0.2 mg/kg of BW p.o) 8 weeks after ovariectomy for 5 weeks (E). After sacrifice, the femurs were reserved for biomechanical, histomorphometric and ash testing. In the biomechanical test, the high-dose UCN rats showed significantly improved mechanical stiffness (341.6 N/mm) compared with the untreated OVX animals (275.9 N/mm). In the histomorphometric evaluation, the high-dose UCN rats demonstrated an improved trabecular microarchitecture especially and significantly at the distal femur (distal femur Tb.Ar = 41.4% and N.Nd/mm(2) = 26.8, proximal femur Tb.Ar = 71.8% and N.Nd/mm(2) = 28.7) compared with untreated OVX rats (distal femur Tb.Ar = 23.3% and N.Nd/mm(2) = 11.7, proximal femur Tb.Ar = 60.2% and N.Nd/mm(2) = 25.2). Our results show that short-term treatment with UCN seems to have a positive effect on the metaphyseal bone structure and strength of the femur in ovariectomized rats.

The Thiocarbamate Disulphide Drug, Disulfiram Induces Osteopenia in Rats by Inhibition of Osteoblast Function Due to Suppression of Acetaldehyde Dehydrogenase Activity

Dithiocarbamates (DTC), a sulfhydryl group containing compounds, are extensively used by humans that include metam and thiram due to their pesticide properties, and disulfiram (DSF) as an alcohol deterrent. We screened these DTC in an osteoblast viability assay. DSF exhibited the highest cytotoxicity (IC50 488nM). Loss in osteoblast viability and proliferation was due to induction of apoptosis via G1 arrest. DSF treatment to osteoblasts reduced glutathione (GSH) levels and exogenous addition of GSH prevented DSF-induced reactive oxygen species generation and osteoblast apoptosis. DSF also inhibited osteoblast differentiation in vitro and in vivo, and the effect was associated with inhibition of aldehyde dehydrogenase (ALDH) activity. Out of various ALDH isozymes, osteoblasts expressed only ALDH2 and DSF downregulated its transcript as well as activity. Alda-1, a specific activator of ALDH2, stimulated osteoblast differentiation. Subcutaneous injection of DSF over the calvarium of new born rats reduced the differentiation phenotype of calvarial osteoblasts but increased the mRNA levels of Runx-2 and osteocalcin. DSF treatment at a human-equivalent dose of 30 mg/kg p.o. to adult Sprague Dawley rats caused trabecular osteopenia and suppressed the formation of mineralized nodule by bone marrow stromal cells. Moreover, DSF diminished bone regeneration at the fracture site. In growing rats, DSF diminished growth plate height, primary and secondary spongiosa, mineralized osteoid and trabecular strength. Substantial decreased bone formation was also observed in the cortical site of these rats. We conclude that DSF has a strong osteopenia inducing effect by impairing osteoblast survival and differentiation due to the inhibition of ALDH2 function.

Vitamin K2 improves femoral bone strength without altering bone mineral density in gastrectomized rats.

Gastrectomy (GX) induces osteopenia in rats. The present study examined the skeletal effects of vitamin K2 in GX rats. Thirty male Sprague-Dawley rats (12 wk old) were randomized by the stratified weight method into the following three groups of 10 animals each: sham operation (control) group; GX group; and GX+oral vitamin K2 (menatetrenone, 30 mg/kg, 5 d/wk) group. Treatment was initiated at 1 wk after surgery. After 6 wk of treatment, the bone mineral content (BMC), bone mineral density (BMD), and mechanical strength of the femoral diaphysis and distal metaphysis were determined by peripheral quantitative computed tomography and mechanical strength tests, respectively. GX induced decreases in the BMC, BMD, and ultimate force of the femoral diaphysis and distal metaphysis. Vitamin K2 did not significantly influence the BMC or BMD of the femoral diaphysis or distal metaphysis in GX rats, but attenuated the decrease in the ultimate force and increased the stiffness of the femoral diaphysis. The present study showed that administration of vitamin K2 to GX rats improved the bone strength of the femoral diaphysis without altering the BMC or BMD, suggesting effects of vitamin K2 on the cortical bone quality.

Pre-suckling calcium supplementation effectively prevents lactation-induced osteopenia in rats

During lactation, osteoclast-mediated bone resorption and intestinal calcium hyperabsorption help provide extra calcium for lactogenesis. Since the suckling-induced surge of pituitary prolactin (PRL) rapidly stimulates calcium absorption in lactating rats, it is hypothesized that pre-suckling oral calcium supplementation should be an efficient regimen to shift the calcium source from bone to diet, thereby slowing lactation-induced osteopenia. Our results showed that 30-min suckling markedly stimulated maternal duodenal calcium transport, which returned to the baseline at 45 min. Lactating rats given 4 mg/kg per dose calcium via a gavage tube at 90 min pre-suckling 4 doses a day for 14 days prevented a decrease in bone mineral density (BMD) of long bones and vertebrae. On the other hand, a single-dose supplementation, despite the same amount of calcium per day, appeared less effective. Because glucose and galactose further stimulated duodenal calcium transport in lactating rats, pre-suckling calcium supplement containing both sugars successfully normalized plasma ionized calcium and led to better bone gain than that with calcium alone. A histomorphometric study revealed that lactating rats given pre-suckling calcium plus monosaccharide supplement manifested greater trabecular bone volume and thickness and exhibited less eroded surface than in vehicle-treated lactating rats. Beneficial effects of the 14-day calcium supplementation persisted until 6 mo postweaning in dams and also elevated the baseline BMD of the offspring. In conclusion, our proof-of-concept study has corroborated that pre-suckling calcium supplements, especially regimens containing monosaccharides, are efficient in preventing osteopenia in lactating rats and could increase bone density in both breastfeeding mothers and neonates.

Effect of dimethyl sulfoxide on inhibition of post-ovariectomy osteopenia in rats

There is increasing evidence that oxidative stress, due to estrogen deficiency, leads to osteopenia. In this study, dimethyl sulfoxide (DMSO), an antioxidant solvent, was used against post-ovariectomy osteopenia (PO) in rats. Forty female rats were divided into 5 groups randomly as follows: Sham, control group; OVX, ovariectomized group; DMSO1, ovariectomized injected DMSO (0.5 ml/kg/d ip); DMSO2, ovariectomized injected DMSO (1 ml/kg/day ip) and DMSO3, ovariectomized injected DMSO (2 ml/kg/d ip). DMSO therapy started 1 week after ovariectomy and continued for 13 weeks. After 13th weeks, sera were prepared, and then L4 vertebrae and right tibial bones rinsed in fixative. Serum bone alkaline phosphatase (BALP), osteocalcin, pyridinoline, malondialdehyde (MDA) and glutathione (GSH) were measured. Trabecular volume density, trabecular and cortex thickness were estimated. Osteoclast and osteoblast numbers were counted morphometrically. The data were analyzed by ANOVA and then post hoc Tukey test at p < 0.05. The increase of pyridinoline and decrease of BALP in DMSO injected groups were inhibited compared with OVX group (p < 0.05). In DMSO injected groups, decrease of bone density, trabecular volume density, thickness of trabecular and tibial cortex were inhibited compared with OVX group (p < 0.05). MDA decreased significantly in DMSO injected groups compared with OVX group. Osteoclast number decreased in DMSO injected groups compared with OVX group (p < 0.05). Osteoblast number did not show significant change in DMSO groups compared with OVX group. In conclusion, DMSO ameliorates PO through decrease of osteoclast number, osteoclast inhibition and osteoblast activation. These effects may probably be mediated via antioxidant property of DMSO.