Osteotropic Effect of Parenteral Obesity in Programmed Male Rats Fed a Calorically Differentiated Diet during Growth and Development.

The experiment was undertaken to assess whether the continuation or change of the parents' diet affects the previously programmed bone metabolism of the male offspring during its growth and development. A total of 16 male and 32 female Wistar rats were divided into groups and fed a standard (diet S) or high-energy (diet F). After the induction of obesity, the rats from groups S and F, as the parent generation, were used to obtain male offspring, which were kept with their mothers until the weaning day (21 days of age). In our earlier study, we documented the programming effects of the diet used in parents on the skeletal system of offspring measured on the weaning day. Weaned male offspring constitute one control group-parents and offspring fed the S diet. There were three experimental groups, where: parents received diet S and offspring were fed with the F diet; parents were treated with the diet F, while offspring received the S diet; and parents and offspring were fed with the diet F. The analyses were performed at 49 and 90 days of life. After sacrifice, cleaned-off soft tissue femora were assessed using peripheral quantitative computed tomography (pQCT), dual X-ray absorptiometry (DXA), and a three-point bending test. We observed that changing and continuation of nutrition, applied previously in parents, significantly influenced the metabolism of the bone tissue in male offspring, and the osteotropic effects differed, depending on the character of the nutrition modification and age. Additionally, an important conclusion of our study, regarding the previous, is that nutrition modification, affecting the metabolism of bone tissue, also depends on the sex.

The Influence of Nesfatin-1 on Bone Metabolism Markers Concentration, Densitometric, Tomographic and Mechanical Parameters of Skeletal System of Rats in the Conditions of Established Osteopenia.

Our study aimed to evaluate the impact of nesfatin-1 administration on bone metabolism and properties in established osteopenia in ovariectomized female rats. In total, 21 female Wistar rats were assigned to two groups: sham-operated (SHAM, n = 7) and ovariectomized (OVA, n = 14). After 12 weeks of osteopenia induction in the OVA females, the animals were given i.p. physiological saline (OVA, n = 7) or 2 µg/kg body weight of nesfatin-1(NES, n = 7) for the next 8 weeks. The SHAM animals received physiological saline at the same time. Final body weight, total bone mineral density and content of the skeleton were estimated. Then, isolated femora and tibias were subjected to densitometric, tomographic, and mechanical tests. Bone metabolism markers, i.e., osteocalcin, bone specific alkaline phosphatase (bALP), and crosslinked N-terminal telopeptide of type I collagen (NTx) were determined in serum using an ELISA kit. Ovariectomy led to negative changes in bone metabolism associated with increased resorption, thus diminishing the densitometric, tomographic, and mechanical parameters. In turn, the administration of nesfatin-1 led to an increase in the value of the majority of the tested parameters of bones. The lowest bALP concentration and the highest NTx concentration were found in the OVA females. The bALP concentration was significantly higher after nesfatin-1 administration in comparison to the OVA rats. In conclusion, the results indicate that nesfatin-1 treatment limits bone loss, preserves bone architecture, and increases bone strength in condition of established osteopenia.

Lipoic acid (LA) dose-dependently protects bone losses in the mandible of rats during the development of osteopenia by inhibiting oxidative stress and promoting bone formation.

Our study was carried out to evaluate the effect of lipoic acid (LA) on the densitometric properties, structure and mechanical strength of the mandible of Wistar rats with developing osteopenia. The study used 42 sham-operated (SHO) and ovariectomized (OVX) rats. The OVX rats were randomly divided (n = 6) onto two controls treated subcutaneously with physiological saline (OVX-PhS) and 17ß-estradiol (OVX-E2), respectively, and onto four experimental OVX groups that received LA in the doses of 12.5, 25, 50 and 100 mg/kg/day for 28 days. The results demonstrated that the lack of estrogen brought about osteopenic bone changes, especially in the trabecular compartment. In addition, while the usage of LA in the doses of 12.5 and 25 LA had no effect in OVX rats, the dose of 100 effectively inhibited osteopenic changes of the mandible. This dose maintained structural, densitometric and mechanical parameters at levels like that in the SHO and OVX-E2 groups by inhibiting the destructive influence of oxidative stress. Dose 50, however, was revealed to be the most effective. It not only inhibited atrophic changes and the influence of oxidative stress, but also stimulated the formation of mandibular bone tissue. Our results suggest that the administration of LA is effective in preventing atrophic changes in the mandibular bone tissue in conditions of ovarian hormone deficiency and suggest its potential in the therapy of osteoporosis.

Programming Effect of the Parental Obesity on the Skeletal System of Offspring at Weaning Day.

Our study aimed to verify the hypothesis of the existence of a programming effect of parental obesity on the growth, development and mineralization of the skeletal system in female and male rat offspring on the day of weaning. The study began with the induction of obesity in female and male rats of the parental generation, using a high-energy diet (group F). Females and males of the control group received the standard diet (group S). After 90 days of dietary-induced obesity, the diet in group F was changed into the standard. Rats from groups F and S were mated to obtain offspring which stayed with their mothers until 21 days of age. Tibia was tested using dual-energy X-ray absorptiometry (DXA), peripheral quantitative computed tomography (pQCT), micro-computed tomography (µCT) and mechanical strength using the three-point bending test. Biochemical analysis of blood serum bone metabolism markers was performed. DXA analysis showed higher tibia bone mineral content (BMC) and area. pQCT measurements of cortical and trabecular tissue documented the increase of the volumetric bone mineral density and BMC of both bone compartments in offspring from the F group, while µCT of the trabecular tissue showed an increase in trabecular thickness and a decrease of its separation. Parental obesity, hence, exerts a programming influence on the development of the skeletal system of the offspring on the day of the weaning, which was reflected in the intensification of mineralization and increased bone strength.

Bone losses in obese, ovariectomized rats appear to be independent from sclerostin-induced inhibition of the Wnt/ß-catenin pathway.

INTRODUCTION: Overweight and obesity, as well as a gonadal function, are pivotal factors influencing bone tissue metabolism. MATERIAL AND METHODS: The aim of the study was to determine the effect of dietary induced obesity (DIO) on bone tissue metabolism in sham-operated (SHO) or ovariectomized (OVX) adult female Wistar rats. Additionally, the influence of DIO in SHO or OVX on the concentration of sclerostin in the blood serum was analyzed. After SHO or OVX, the rats were placed in groups (n=8) and either received a standard diet (11.5 MJ/kg) (SHO-CON; OVX-CON) or a high-energy diet (17.6 MJ/kg) (SHO-FAT; OVX-FAT). The experiment lasted for 90 days and allowed for the establishment of osteopenia in OVX females and obesity in the rats that had received the high-energy diet. RESULTS: The results of the study demonstrate that obesity or/and ovariectomy increases the resorption of femora and tibiae, hence decreasing the densitometric and mechanical parameters affecting the bone structure in adult females rats. The strongest osteodegenerative effect was seen in the OVX-FAT females. Interestingly, the degree of bone tissue degradation caused exclusively by ovariectomy was similar to that found in the obese sham-operated rats. CONCLUSIONS: Bone losses invoked by DIO seem to be independent from the Wnt/ß-catenin pathway inhibition induced by sclerostin. While further study is necessary, the obtained results suggest that the usage of sclerostin anti-body in the treatment of osteoporosis can be ineffective, and in obese patients the undertaking of such therapy should be reassessed.

The effect of fructan-enriched diet on bone turnover parameters in ovariectomized rats under calcium restriction.

INTRODUCTION: Osteoporosis, the "quiet epidemic", is one of the most serious threats to public health. It is known that estrogen plays a significant role in the regulation of bone turnover, and its loss at menopause causes osteoporosis. Added to this, insufficient calcium intake accelerates bone mass loss, increasing the risk of fractures. OBJECTIVE: The study aimed to answer the question whether a fructan-enriched diet could be helpful in preventing from disturbances in bone turnover caused by calcium restriction combined with ovariectomy-induced estrogen deficiency. The differences related to the kind of fructan and 'matrix effect' of fructan action (form of addition) were also evaluated. MATERIAL AND METHODS: The study was conducted using sham-operated (control groups) or ovariectomized (OVX) rats fed a calcium restricted diet. The treatment diets contained one of three fructan sources - Jerusalem artichoke, yacon and Beneo Orafti Synergy1 - added alone or as an ingredient of strawberry sorbet, all in the amount providing 8% fructans. Analyses of biological material included: serum Ca, Mg and P concentrations, alkaline phosphatase activity (ALP), osteocalcin (OC) and C-telopeptide degradation products from type I collagen (CTX). Densitometric parameters of femora were also assayed. RESULTS: Among markers of bone turnover, the ALP activity depended both on the kind of fructan and the form of addition. The highest value was shown in the OVX group fed a low-calcium diet, whereas administration of diet enriched with Jerusalem artichoke led to an almost 50% decrease in the value of this parameter. Dietary fructans also lowered the OC level. Feeding rats with diet containing sorbet enriched in yacon or Jerusalem artichoke resulted in a decrease of CTX, compared to the diet containing yacon alone or fructan formulation in both forms No significant differences were observed in densitometric parameters between treatment groups. CONCLUSIONS: The obtained findings suggest that fructan administration with a calcium-restricted diet might exert a positive effect on bone turnover parameters. Regarding the form of their addition, it is possible that other constituents of sorbets contributed to the fructan action. It remains open whether this impact would be significant over a longer period of time.

Could fructan sources in strawberry matrix be more effective as a tool for improvement of bone structure than these compounds added to diet alone? - Study on osteopenic rat model.

INTRODUCTION: Osteoporosis, a disease associated with ovarian hormone deficiency following menopause, is the most common cause of age-related bone loss. Although an optimal intake of Ca is vital - both bone accretion during growth and maintenance in adult life - a great percentage of the population consumes far below the recommended amounts of this mineral. On the other hand, there are evidences that fructans enhance not only Ca absorption, but bone calcium as well. OBJECTIVE: In the knowledge that estrogen deficiency and insufficient Ca in the diet during postmenopause cause serious problems with resultant osteoporosis, the aim of this study is to assess the effects of a diet enriched in fructan-containing sources alone, or in the "strawberry matrix", on the structure of bone in OVX rats under calcium hypoalimentation. MATERIAL AND METHODS: Experimental animals were female Wistar rats, sham-operated or ovariectomized. The treatment with Ca-restricted diets also contained one of the sources of fructan (Jerusalem artichoke, yacon, Beneo Orafti Synergy1), in the amount providing 8% of fructans. Femur architecture of rats was assessed by tomography and Ca content by the AAS method. RESULTS: Ovariectomy led to a significant decrease in femoral Ca content, total mineral content and bone density of rats. This study shows that a diet containing inulin-type fructan (especially as a component of strawberry product) improved bone quality (i.e. increase in Ca content in femur, total density in middle part of bone, as well as decrease of endosteal circumference) in OVX rats under calcium hypoalimentation. CONCLUSIONS: These findings suggest that a fructan-enriched diet could be potentially useful for postmenopausal osteoporosis. It is important to determine an optimal dietary level of fructan with the long-term goal of developing a dietary strategy in osteoporosis prevention.

Nesfatin-1 prevents negative changes in bone in conditions of developing osteopenia.

OBJECTIVE: The aim of the study was to determine the effect of nesfatin-1 on bone properties in female rats in the conditions of developing osteopenia induced by ovariectomy (OVX). MATERIAL AND METHODS: The experiment was performed on 21 female Wistar rats assigned to 3 groups receiving intraperitoneally physiological saline (SHO, OVX-PhS) and nesfatin-1 in dose 2 µg/kg BW of (OVX-NES) once a day for 8 wks. At the end of the experiment, the rats were scanned using the DXA method to determine the body composition, tBMC, and tBMD. The isolated femora and tibia were tested with the DXA method for BMD and BMC, and with the pQCT method for separate analysis of the cortical and trabecular bone tissue. The bone strength parameters were also determined. The immunohistochemical method was used for determination of nesfatin-1 localization in growth cartilage. Bone metabolism markers (osteocalcin, bALP, and NTx) were identified using an ELISA kit. RESULTS: OVX exerts a negative effect on bone tissue. The nesfatin-1 administration influenced positively the DXA parameters of tibia. TvBMD and TbvBMD measured by pQCT in metaphysis of bones were significantly higher in the OVX-NES group than in OVX-PhS. No differences were found in the values of bone strength parameters between SHO and OVX-NES females. Extra- and intracellular immunohistochemical reaction for nesfatin-1 was observed in all zones of growth cartilage, with the strongest reaction detected in the calcifying zone. Nesfatin-1 administration caused a significant increase in the osteocalcin and bALP concentration in relation to the OVX-PhS animals. CONCLUSIONS: The results of the experiment indicate that nesfatin-1 exerts a protective effect on bone tissue properties and can be used in the prevention of osteoporosis.

Fructan-Enriched Diet Increases Bone Quality in Female Growing Rats at Calcium Deficiency.

This study was designed to determine the effect of feeding female rats with low-calcium diet containing one of three fructan sources (Jerusalem artichoke, yacon, Beneo Orafti Synergy1), on selected bone parameters. Growing Wistar rats were fed modified AIN-93 G diet enriched in fructan sources (8%), added alone or as a strawberry sorbet ingredient. Two of eight groups were a validation model, where the positive control group was fed with recommended calcium dose in the diet (RCD), and negative one - with low calcium diet (LCD). After 12 weeks, femoral Ca content, bone densitometry, architecture and hardness were examined. The positive effects on femoral Ca content and cortical thickness, area and content in distal part of bone was observed after feeding animals diet enriched in Jerusalem artichoke sorbet. Beneficial action on other bone tomographic parameters (particularly trabecular volumetric bone mineral density) in this part of femur were associated mainly with the consumption of the diet with sorbet containing yacon. Our results showed an important role of diet containing frozen strawberry desserts enriched in fructan sources in the maintenance of healthy bones of growing organism. It may suggest possible synergisms between fructans and bioactive substances of strawberry.

The peripheral quantitative computed tomographic and densitometric analysis of skeletal tissue in male Wistar rats after chromium sulfate treatment.

INTRODUCTION: This study evaluates the effects of three different doses of chromium sulphate on bone density and the tomographic parameters of skeletal tissue of rats. MATERIAL AND METHODS: The experiment was performed on 40 male Wistar rats which received, by gavage, during 90 days, a chromium sulphate in either a daily dose of 400, 600 or 800 µg/kg BW. At the end of experiment, the rats were scanned using the densitometry method (DXA) to determine the bone mineral density, bone mineral content of total skeleton and vertebral column (L2-L4) and parameters of body composition (Lean Mass and Fat Mass). The isolated femora were scanned using peripheral a quantitative computed tomography method (pQCT) for a separate analysis of the trabecular and cortical bone tissue. The ultimate strength, work to ultimate and the Young modulus of femora was also investigated by the three-point bending test. RESULTS: The negative impact of chromium was observed in relation to bone tissue. All doses significantly decreased total skeleton density and mineral content, and also had impact upon the isolated femora and vertebral column. Trabecular volumetric bone mineral density and trabecular bone mineral content measured by pQCT in distal femur metaphysis were significantly lower in the experimental groups than in the control. Higher doses of chromium also significantly decreased values of ultimate strength and Young modulus in the investigated femora. CONCLUSIONS: The results of the experiment demonstrate that chromium sulphate is dose dependent, and exerts a disadvantageous effect on the skeleton, as it decreases bone density and resistance.

Lipoic acid stimulates bone formation in ovariectomized rats in a dose-dependent manner.

This study was undertaken to determine the osteotropic effect of different doses of lipoic acid (LA) on the mineralization of bone tissue in female Wistar rats with experimental osteopenia induced by bilateral ovariectomy. Fifty-six rats were randomly selected and submitted to either a sham operation (n = 8) or an ovariectomy (n = 48). The ovariectomized rats were randomly placed into two control groups, treated subcutaneously with either physiological saline or 17ß-estradiol in the dose of 4 µg/kg body mass per day, and four experimental groups that received LA subcutaneously in the doses of 12.5, 25, 50, and 100 mg/kg body mass per day (n = 8 in each group). After 28 days of experimental treatment, the rats were sacrificed, and body mass, total skeletal density, and body composition were recorded. Blood serum and isolated femora were stored for further analysis. Our results revealed that the osteoprotective effect of LA was dose-dependent and was observed in rats treated with 50 and 100 mg/kg of LA. Moreover, the LA applied to the ovariectomized rats in the dose of 50 mg/kg not only stopped the bone resorption, but stimulated its formation.

Anti-osteopenic effect of alpha-ketoglutarate sodium salt in ovariectomized rats.

The purpose of the study was to determine the effect of alpha-ketoglutarate sodium salt (AKG) treatment on the mineralization of the tibia in female rats during the development of osteopenia (Experiment-1) and in the condition of established osteopenia (Experiment-2). Thirty-two female rats were ovariectomized (OVX) to induce osteopenia and osteoporosis and another 32 female rats were sham-operated (SHO) and then randomly divided between the two experiments. In Experiment-1, the treatment with AKG started after a 7-day period of convalescence, whereas in Experiment-2 the rats were subjected to a 60-day period of osteopenia fixation, after which the actual experimental protocol commenced. AKG was administered in the experimental solution for drinking at a concentration of 1.0 mol/l and a placebo (PLC) was used as a control solution. After 60 days of experimental treatment the rats in both experiements were sacrificed, the body weight recorded, and blood serum and isolated tibia were stored for further analysis. The bones were analyzed using tomography and densitometry, and for estimation of mechanical properties the 3-point bending test was used. Serum concentrations of osteocalcin and collagen type I crosslinked C-telopeptide were measured. The anabolic effects of AKG on bone during osteopenia development in Experiment-1 not only stopped the degradation of bone tissue, but also stimulated its mineralization. The usage of AKG in animals with established osteopenia (Experiment-2) was not able to prevent bone atrophy, but markedly reduced its intensity. The stimulation of tibia mineralization after AKG treatment has been also argued in healthy SHO animals. The results obtained prove the effectiveness of AKG usage in the prophylaxis and therapy of osteopenia and osteoporosis, induced by bilateral gonadectomy. Additionally, the results clearly prove that treatment with AKG improves the mineralization of bone tissue in healthy animals.