Efeitos da suplementação de extratos de linhaça e/ou amoreira sobre o sistema ósseo de ratas ovariectomizadas

Abstract

Estrogens (E2) are steroid hormones, produced in high amounts since puberty by the ovaries, which promote their actions, mainly in reproductive organs development, but also act in bone formation modulation. Decrease in E2 concentration in plasma as a result of ovarian failure, surgical removal or use of receptor blockers, may have effects that can lead to osteoporosis. Hormone replacement therapy can cause collateral damage, which leads to search for new alternatives, such as use of foods rich in nutraceuticals that have relative amounts of phytoestrogens. Flaxseed (Linum usitatissimum) and blackberry (Morus nigra L.) leaves, petioles and stems are examples of nutraceutical sources. Thus, the objective of this work was to verify the effects promoted by supplementation with flaxseed and/or mulberry extracts in ovariectomized rats. For this, female Wistar rats (n=32) were submitted to bilateral ovariectomy and treated with flaxseed (400 mg/kg), mulberry (400 mg/kg), flaxseed + mulberry (200 mg/kg each) extracts, E2 (0.158 mg/kg) or saline, daily, for 60 days. Femurs and blood samples were collected for analysis. Quantification of bone cells and trabecular percentage were performed on histological slides, -CT for observation of morphometric changes, and SEM-EDS for minerals quantification in femoral head and neck regions, as well as activity measurement of bone alkaline phosphatase activity (ALP) in plasma. The results were analyzed by Scott-Knott at 5% statistical significance. A greater number of osteoblasts and osteoclasts was observed in the bones of animals treated with mulberry extract. Animals treated with extracts showed lower percentage of trabeculae loss, bone mineral density, bone volume, number of trabeculae, and were able to maintain porosity and intertrabecular space. Calcium, phosphorus, and magnesium concentrations were higher in femurs of animals treated with the extracts compared to those receiving saline. There was greater ALP activity in animals treated with the extracts, similar to those treated with estrogen. Thus, it is suggested that flaxseed and/or mulberry extracts were able to prevent bone loss caused by the lack of estrogenic action in female rats, possibly acting in the modulation of the control of bone resorption, suggesting that this supplementation can prevent/reduce effects caused by hormonal depletion.