Impact of an obesogenic diet program on bone densitometry, micro architecture and metabolism in.. Fat mass accumulation induces changes in body composition that affect the bone health. The effect of body mass on the skeleton remains controversial although numerous studies in the literature exist concerning obese subjects . Metabolism is a modern architecture movement originating in Japan and most influential in the 1960s—trending roughly from the late 1950s to the early 1970s. Metabolic, Physiologic, and. Metabolic Architecture of the Cereal Grain and Its Relevance to Maximize Carbon Use Ef Some studies have shown that obese adolescents have higher bone mineral density (BMD) than their normal- weight controls . Alternatively, other studies have shown an inverse relationship between bone mass and fat mass after adjustment for body weight . In animals, the effects of high fat/high sucrose diet (HF/HS) on bone health are also controversial . Since the experimental methods are quite disparate between studies, it is not surprising that findings are discordant as well. These discrepancies could be explained by the different animal characteristics (gender, age and race), the duration and the quality of the diet used. Metabolic Diet Sample Meal PlanBut the most important factor that could also influence the results is the ability of the diet to induce or not obesity. By inducing mechanical load on the skeleton, the excess of fat mass is strongly linked to bone tissue. Some studies reported improvements of biomechanics and microarchitecture of femur in rodents previously fed with diets inducing obesity . Bramhabhatt et al. They suggested that obese rats had favorably adapted their bone tissues and improved their biomechanical properties compared to rats “resistant” to the diet. ![]() Metabolic Diet Menu Examples![]() Such results show that obesity must be taken into account when performing relevant comparisons between studies. Indeed, when HF or HF/HS diet does not induce obesity, the rats develop lower bone mineral density or worst bone mechanical properties . There is a consistent positive association between body mass and bone mass. Conversely, weight loss is linked to a concomitant accelerated loss of bone mass . Dietary factors are known to influence BMD. Several studies have examined the association between the type of dietary fat and BMD in humans but again the results are conflicting. Thus, saturated fatty acid intake was found to correlate inversely to the BMD in men and women in NHANES cohort study . Until now, only few studies have analyzed the effect of an obesogenic diet on bone characteristics in male rats and none of them have assessed the cellular activity of bone remodeling. ![]() Therefore, the purpose of the present study was to investigate the bone cellular activity, density and micro architecture response to body composition changes induced by an HF/HS diet in male rat. Methods. Animal care and experimental diet. All experimental designs and procedures were made in accordance to the current legislation on animal experience in France and were approved by the ethical committee for animal experimentation (CREEA Auvergne, CE1- 0. Forty- three 6- month old Wistar male rats (CERJ Janvier. After one month of acclimatization with a standard rodent diet, animals (aged of 7months) were randomized into three groups: 1. Keeping your metabolism. Metabolism Type Test Adapted from The Metabolic Typing Diet (Wolcott and Fahey 2000, 135), this simple test is the most basic way to determine your metabolism type. ![]() ![]() ![]() HF/HS, n=1. 4); 1. Control, n=1. 5) and 1 group sacrificed before the diet (BD, n=1. The rats had free access to water. The composition of the diets and repartition of types of fatty acids are given Table . HF/HS diet was mainly enriched in sucrose, saturated fatty acids and cholesterol (provided by lard) resulting in omega. Although the diet differed in dietary composition, each provided similar daily amounts of protein, cellulose, vitamins and minerals to the animals based on the two groups being fed the same daily caloric intake. In order to control that all groups consumed equal amounts of calories each day, the diets were prepared in individual ramekins and removed daily. Finally, ninety five kcal of food per day were given to all rats. Composition of the experimental diets and type of fatty acid. Dissection of rats. Rats were fasted for 1. They were euthanized by decapitation under isoflurane anesthesia. Visceral fat mass was assessed by weighing the total perirenal and peri- epididymal adipose tissues. The weights of these two tissues were combined to form the ex- vivo Fat Mass. Right tibia and L2 vertebrae were removed for bone microarchitecture and histomophometric analyses. Left tibia was removed for densitometric analyses. Abdominal circumference measurement (AC)Abdominal circumference (AC) was assessed on all rats on the largest circumference of the rat abdomen using a plastic non extensible measuring tape (Rollfix, Hoechstmass. Rats were placed in ventral position. It was shown that the AC measure could be a useful biometric technique for assessing in- vivo abdominal fat mass storage in fat rats . The CV for AC measures (2. The same operator repositioned the measuring tape three times. Oral glucose tolerance tests (OGTT)All rats were subjected to an OGTT one week before sacrifice. After 1. 3 hours fasting, blood samples were collected from the tail vein using heparinized capillary tubes. The rats were then given a glucose load solution by gavage (1g/kg of body weight) and vein tail blood was collected 1. The blood samples were centrifuged at 1. The glucose and insulin responses during the OGTT were computed from the area under the curve (AUC) using the trapezoidal method . The blood samples were immediately centrifuged and plasma was stored at . All biochemical measures were assessed in duplicate. Lipids profile of all rats (total cholesterol, HDL cholesterol, triglycerides, non- esterified fatty acids (NEFA),) was measured in plasma samples by using an automated analyser (Konelab 2. Thermo Electron Corporation). Chemicals were obtained from Thermo Fischer (Thermo Fisher Scientific, Vantaa, Finland). The intra assay coefficients of variations were 2. HDL cholesterol, triglycerides and NEFA respectively. The inter assay coefficients of variation were 4. HDL cholesterol, triglyceride and NEFA respectively. LDL cholesterol level had been determined using Freidwald formula (LDL cholesterol=Total Cholesterol - HDL cholest. The inter assay coefficient of variations were 6. The bone turnover markers have been measured on plasma of eight rats per group. Bone formation was measured by serum level of osteocalcin using Elisa essays (Rat- MID. The intra- assay coefficients of variation were 9. CTX and osteocalcin respectively. The inter assay coefficient of variations were 1. CTX and osteocalcin respectively. In order to assess the relative balance of the formation and resorption, we calculated the bone uncoupling index (UI) . Using the BD group values as reference data, z scores of formation and resorption markers were calculated for each rats. Then, the UI was calculated as the average of the z score for the bone formation marker minus the bone resorption marker. A positive UI indicates that bone formation was predominant while and a negative UI indicates an imbalance favouring resorption . After 4. 8 hours of fixation with formol (1. L2 vertebrae of seven rats per groups were embedded in methylmethacrylate at a low temperature with known techniques (2. The central plane of metaphyses of the tibia was sliced frontally with a microtome (Reichert- Jung Polycut, Heidelberg, Germany). Nine micrometers thick slices were retrieved for Goldern’s trichrome and Tartrate- resistant Acid Phosphatase (TRAc. P) (5 slices each) and Toludin blue (2 slices) colorations. Dynamic parameters were evaluated from five unstanded slices of 1. The following parameters were measured in the secondary spongiosa according to the ASBMR histomorphometry nomenclature (Parfitt et al., 1. BIOCOM, Lyon, France): BV/TV, Tb. Th, and osteoid surface (OS/BS, %). TRAc. P staining permitted the measurements of osteoclastic surfaces activity (Oc. S/BS) and osteoclast number (N. Oc). Histodynamic parameters were determined under UV light: mineral apposition rate (MAR, . Mineralizing surface per bone surface (MS/BS, %) was calculated by adding d. LS/BS and one- half s. LS/BS. Bone formation rate (BFR/BS, . The aforementioned parameters of bone resorption and formation were measured with a semiautomatic system consisting of a digitizing table (Summasketch- Summagraphics, Paris, France) connected to a personal computer and a Reichert Polyvar microscope equipped with a drawing system (Camera Lucida; Reichert- Jung Polyvar). High resolution micro tomography (. Trabecular network is qualified by the plate- rod characteristic of the structure (Structure Model Index), the geometric degree of anisotropy and connectivity density. The tibia secondary spongiosa was scanned within the metaphysis below the growth plate and the cortical bone of tibia was scanned in the diaphysis. The L2 secondary spongiosa was scanned between the two growth plates. Exactly, 6. 45 slices were set for total acquisition in both tibia and vertebrae. The cortical ROI of tibia identified 1. Data were acquired at 5. V, with a 1. 0. Three- dimensional reconstructions were generated using the following parameters: Sigma: 1. Support: 2, Threshold: 2. The structural parameters of trabecular bone: bone volume fraction (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N), trabecular separation (Tb. Sp), structure model index (SMI), connection density (Conn. D.) and degree of anisotropy (DA) were generated from a set of 2. Cortical porosity was calculated as follows: Cortical porosity=(1 – (BV/TV) *1. Ex- vivo densitometry. Densitometric parameters of the left tibia were assessed by a densitometer designed for small animal body composition (PIXImus, Lunar. Total bone mineral density, bone mineral content and bone area have been assessed. Results. Final body composition, visceral fat, central fat mass and abdominal circumference. Final body composition, visceral fat, central fat mass and abdominal circumference values are given Table . HF/HS group displayed significantly higher global mass, global fat and bone mass (p< 0. Control group. HF/HS group had also higher global fat percentage, abdominal fat mass, central fat mass and ex vivo fat mass than Control group (p< 0.
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