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Abstract
Objective: The aim of this study was to evaluate the effect of supplemented different doses of sodium tetraborate as a source of boron on bone characteristics; bone mechanical properties; some female sex hormones; some mineral contents; cell-mediated immune response and hypolipidemia in adult female albino rats.
Design: Eight groups each of eight adult female Albino rats, Sprauge Dawley strain, mean weight varied between 156.2 to 158.8 g were used. The experimental animals were fed the basal diet (control group) or the basal diet supplemented with 5, 10, 15, 20, 25, 30 and 35 mg B/100g diet for 6 weeks.
The cell-mediated immune response was assessment by an interadermal injection with 0.1 ml of phytohemagglutinin (PHA) (150 µg/ 0.1 ml) in the flank region on both the right and the left sides. Inflammatory response was measured as a change in skinfold thickness prior to and at 6, 12, 24, and 48h after PHA injection. In addition, serum levels of follicle stimulating hormone (FSH); luteinzing hormone (LH); progesterone ;17β-estradiol (E2); calcium; inorganic phosphorus; magnesium; total cholesterol; triacylglycerols; and alkaline phosphatase (ALP) activity were measured. Also, bone ash content; bone characteristics; and mechanical properties of right and left entire long bone (femur and tibia) were measured. Finally, bone specimens were processed for histopathological examination.
Results: The results indicated that, boron supplementation affected body weight gain, femur and tibia bone weight, density, mechanical properties ( moment of inertia and stress) , total lipids, and minerals ash content (calcium, inorganic phosphorous, magnesium, and copper). On the other hand, different experimental doses of boron have no effect on food intake, femur and tibia bone length, mineral ash content of zinc, and bending moment of tibia bone. In addition, the results revealed that, a statistical significant increase was observed in mean values of femur bending moment in the experimental rat groups fed on diets containing high doses of boron as sodium tetraborate. Cell-mediated immune response was increased by dietary boron supplementation at 6h after injection compared to zero time. At 12h after injection cell-mediated immune response had the lowest values in all rat groups fed diets containing different doses of dietary boron (5 to 35 mg B/ 100 g diet).Serum levels of FSH and LH were not affected by boron supplementation. While, serum concentration of 17β-estradiol increase a significantly by increasing boron supplementation. Whilst, serum level of total cholesterol and triacylglycerols were decreased in rats fed diets supplemented with (20 to 35 mg B/ 100 g diet).While, serum level of ALP activity was reduced in all treated groups compared to control group. Serum levels of calcium were increased in rat groups fed diet containing (10 to 25 mg B/ 100 g diet) and then decreased as the supplementation of dietary boron increased (30 and 35 mg B/ 100 g diet). Microscopically examination of bone from group 5 to group 8 revealed dense bone matrix, diminished marrow cavities and hyperactivity of osteoblasts, as well as appearance of newly formed bony trabeculae.
Conclusion: These results suggest that physiologic amounts of boron may have beneficial effects upon bone minerals metabolism and consequently, bone characteristics. Also, dietary B supplementation has regulatory effect on cell-mediated immune response, increased estrogen level and maintenance of bone which may have a preventive effect on the development of osteoporosis.