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Despite its apparent stability, bone tissue is an extremely dynamic structure, responding to diverse and multidirectional interactions by changes in its metabolism. Adipose tissue is no longer seen as a mere store of energy reserves for the organism, but is also recognized as an important endocrine organ. There are several relationships between the two types of tissue, which result from the influence of fat tissue on bone tissue. This influence is expressed through a direct influence of adipokines on bone metabolism and through indirect effects and regulatory impact of adipose tissue on other hormones associated with the metabolism of bone tissue. Osteotropic effects of adipose tissue also result from mechanical load on the skeleton. The aim of this paper was to present the mechanisms of mutual interactions between adipose tissue and bone tissue. The authors also tried to answer the question of whether obesity promotes the development of osteoporosis or whether it is a protective factor for the skeletal system.
The purpose of the study was to determine the effect of Strontium Ranelate (RS) on the mineral density and mechanical properties of the femur in male Wistar rats during experimental osteopenia induced by bilateral gonadectomy. After adaptation, the rats were randomly divided and subjected to sham-operations (SHO) (n = 10) and bilateral orchidectomy (ORX) (n = 20). ORX rats were subsequently divided into the control group (ORX/K) and experimental group treated with RS (ORX/RS), administered by gavage, at a dose of 900 mg/kg b.w. The experiment lasted 60 days and then the animals were killed, blood collected, and femora isolated. Femora were analyzed using peripheral quantitative computed tomography (pQCT) to determine volumetric bone mineral density of the cortical part of the shaft of the column (Ct.vBMD), endoosteal and periosteal circumferences, cortical thickness (Ct.Th) and Strength Strain Index (SSI). Measurements were performed on 50% of bone length. The bones were tested using the three-point bending test to estimate ultimate strength and resilience. The activity of alkaline phosphatase (ALP) and concentrations of Ca and P in the blood serum were estimated. The obtained results indicated that the use of strontium ranelate in orchidectomized rats over a period of 60 days not only inhibited the reabsorbing processes induced by a lack of gonad steroids but also accelerated processes of new bone tissue formation, which improved their mechanical parameters and ultimate strength and maximum elasticity.
The study aimed at the determination of dynamic relationship between mineralisation processes and antioxidative/oxidative status during the development of osteopenia. One hundred and two healthy female Wistar rats at the age of 2 months and initial body weight of 200 g were used in the experiment. The rats were divided into control (CON, n=6), sham operated (SHO, n=48), and ovariectomised (OVX, n=48) groups. Animals from SHO (n=6) and OVX (n=6) groups were sacrificed every week during 8 weeks of the experiment in order to detect dynamic changes in examined parameters. The samples were collected weekly from day 7 to day 56. The femora were examined with the use of DXA (bone mineral density) and pQCT (area, mineral content, volumetric density of trabecular and cortical part of distal femora). The pQCT scans were performed 5 mm from distal end of the tibia. Hie determination of activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in haemolysates of erythrocytes were performed spectrophotometrically. Obtained data showed wave like changes in both enzyme activities and bone parameters and indicated the importance of the 2nd -3rd and 5th -6th week after surgery as a key moment for bone metabolism and activity of enzymatic antioxidative defence during the development of osteopenia induced by bilateral ovariectomy. The obtained results proved that alterations in activity of GSH-Px and SOD, and pQCT ahead the changes registered by DXA by 7 d.
The aim of the study was to investigate the influence of [D-Lys3]-growth hormone releasing peptide-6 (GHRP-6), an antagonist of GHS-R1a, on the growth performance and properties of bone tissue in rats. The studies were performed on 12 male Wistar rats, divided into two equal groups. Control rats received 0.5 ml of physiological saline, while experimental rats received intragastrically 100 nmol/kg b.w. of [D-Lys3]-GHRP-6 once a day, throughout 4 weeks. After that time, the animals were subjected to euthanasia. tBMC, tBMD, lean mass (LM), and fat mass (FM) contents were measured using DEXA methods. Plasma level of total ghrelin was also measured. The quality of the femur and tibia was estimated based on their weight, length, BMC, and BMD. [D- Lys3]-GHRP-6 decreased final body weight, LM content, and tBMD, and significantly reduced bone weight and BMC as compared to the control group. No significant differences were noted in bone length and BMD. Plasma level of total ghrelin was significantly higher after the treatment. We concluded that the intragastric treatment with [D-Lys3]-GHRP-6 negatively influenced the growth performance and properties of bone in rats. Therefore, ghrelin probably achieves effect in bone by acting on its specific receptor GHS-R1a.
The objective of this study was to evaluate the effect of dietary conjugated linoleic acid (CLA) and false flax (Camelina sativa) seed oil (CS) on bone quality in broiler chickens. Experiment was carried out on 96 chickens randomly divided into four groups: control group fed diet with sunflower oil (SO) and three experimental groups fed diet with addition of CLA (2.86% starter, 4.32% grower) and diet with addition of CLA (1.43% starter, 2.16% grower) and SO or CS (1.43% starter, 2.16% grower). On the 35th d of life eight birds per treatment were slaughtered and the femur, humerus, and tibia were isolated for further analysis. Using DXA method, bone mineral content (BMC) and bone mineral density (BMD) were measured. Furthermore, weight and length of bones were assessed. The weight, BMD, and BMC in chickens from CS+CLA group were significantly higher when compared with CLA group. The significant differences were noted for BMC between control and CS+CLA birds. No marked differences of bone parameters were observed between control group and CLA, and SO+CLA groups. In conclusion, the results indicate that false flax oil and CLA can replace sunflower oil in chickens feeding, and demonstrate the effectiveness of false flax oil on the enhancement of bone properties in broiler chickens.
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