Biological effects of tolerable level chronic boron intake on transcription factors

Effects of Boron-Containing Compounds on Liposoluble Hormone Functions

Boron-containing compounds (BCC), particularly boronic acids and derivatives, are being increasingly tested as diagnostic and therapeutic agents. Some effects of BCC involve phenomena linked to the action of steroid or thyroid hormones; among these, are the effects on muscle mass or basal metabolism. Additionally, some toxicology reports on mammals, including humans, sound an alert concerning damage to several systems, among which are the negative effects on the induction of male infertility. Systemic and local mechanisms to explain changes in metabolism and impaired fertility were collected and presented. Then, we presented the putative pharmacodynamic and pharmacokinetic mechanisms involved and demonstrated in these events. In addition, it is proposed that there are adducts of some oxygenated BCC with cis-diols in fructose, an essential source of energy for sperm–cell motility, an uncoupling of sex hormone-binding globulin (SHBG) and its ligands, and the modulation of the DNA synthetic rate. These effects share the reactivity of boron-containing compounds on the cis-diols of key molecules. Moreover, data reporting no DNA damage after BCC administration are included. Further studies are required to support the clear role of BCC through these events to disrupt metabolism or fertility in mammals. If such phenomena are confirmed and elucidated, an advance could be useful to design strategies for avoiding BCC toxicity after BCC administration, and possibly for designing metabolism regulators and contraceptive drugs, among other purposes. Boronic derivatives and carboranes have been proposed and studied in this field.

Cell-Seeded Biomaterial Scaffolds: The Urgent Need for Unanswered Accelerated Angiogenesis

One of the most arduous challenges in tissue engineering is neovascularization, without which there is a lack of nutrients delivered to a target tissue. Angiogenesis should be completed at an optimal density and within an appropriate period of time to prevent cell necrosis. Failure to meet this challenge brings about poor functionality for the tissue in comparison with the native tissue, extensively reducing cell viability. Prior studies devoted to angiogenesis have provided researchers with some biomaterial scaffolds and cell choices for angiogenesis. For example, while most current angiogenesis approaches require a variety of stimulatory factors ranging from biomechanical to biomolecular to cellular, some other promising stimulatory factors have been underdeveloped (such as electrical, topographical, and magnetic). When it comes to choosing biomaterial scaffolds in tissue engineering for angiogenesis, key traits rush to mind including biocompatibility, appropriate physical and mechanical properties (adhesion strength, shear stress, and malleability), as well as identifying the appropriate biomaterial in terms of stability and degradation profile, all of which may leave essential trace materials behind adversely influencing angiogenesis. Nevertheless, the selection of the best biomaterial and cells still remains an area of hot dispute as such previous studies have not sufficiently classified, integrated, or compared approaches. To address the aforementioned need, this review article summarizes a variety of natural and synthetic scaffolds including hydrogels that support angiogenesis. Furthermore, we review a variety of cell sources utilized for cell seeding and influential factors used for angiogenesis with a concentrated focus on biomechanical factors, with unique stimulatory factors. Lastly, we provide a bottom-to-up overview of angiogenic biomaterials and cell selection, highlighting parameters that need to be addressed in future studies.

Effects of Selenium Yeast in Combination with Boron on Muscle Growth and Muscle Quality in Broilers

The effect of selenium yeast in combination with boron on both growth and quality of the muscle in broilers was investigated. A total of 600 one-day-old Arbor Acres broilers were randomly divided into five groups with 120 broilers per group (6 replicates per group). The control group received a basal diet, and experimental groups I-IV received the same basal diet supplemented with 0.3 mg/kg selenium yeast and different doses of boron (0, 5, 10, and 15 mg/kg, respectively). The experiment was conducted for 42 days. Breast and thigh muscles were harvested and muscle quality were examined on day 21 and day 42 of the experiment. Compared to the control group, at 21 days of age, the thigh muscle weight and index were significantly increased in broilers of experimental group II (all P < 0.05); however, the drip loss and shear force of breast and thigh muscle were significantly decreased (P < 0.05). At 42 days of age, the breast muscle weight and index as well as the breast and thigh muscle water holding capability had significantly increased in broilers of experimental group II (all P < 0.05); the breast and thigh muscle drip loss, cooking loss and shear force, and thigh muscle fiber diameter were significantly reduced (all P < 0.05). Breast and thigh muscle fibers were tightly arranged with small cross-sectional areas in broilers of experimental group II. These results suggest that supplementation of 0.3 mg/kg selenium yeast in combination with 5 mg/kg boron in the basal diet can promote muscle growth and improved muscle quality in broilers.

Boron intake, osteocalcin polymorphism and serum level in postmenopausal osteoporosis

The relationship between daily boron intake and osteocalcin-mediated osteoporosis was studied in boron-exposed postmenopausal women. It is known that boron and osteocalcin are important in bone metabolism, however the effect of boron in bone metabolism has not been fully discovered. The study was performed on 53 postmenopausal women aged 55-60 living in parts of Balikesir, Turkey, where the subjects are naturally exposed to high (≥1 mg/L) or low (<1 mg/L) boron concentration in drinking water. 24-h urine samples were collected from all participants and creatinine clearance was detected. Boron intake levels of the subjects whose clearance levels were between 80-124 mL/min were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) in urine samples. Serum osteocalcin levels of the subjects were measured by osteocalcin enzyme-linked immunosorbent assay (ELISA) kit. Osteocalcin polymorphism rs1800247 was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Serum osteocalcin levels in boron-exposed postmenopausal women were significantly higher than that of control group (P ≤ 0.05) and the correlation between the serum osteocalcin level and rs1800247 polymorphism was not significant in both groups (P > 0.05). The differences in the distribution of osteocalcin genotypes and alleles in postmenopausal women were not significant between the boron exposed and the control groups (P > 0.05). Serum osteocalcin level in the CC genotype was significantly higher compared to the TC genotype in boron-exposed group (P ≤ 0.05). Our study suggests that daily boron intake of 1 mg/L may affect bone metabolism in postmenopausal women positively.

Effect of Boron on Thymic Cytokine Expression, Hormone Secretion, Antioxidant Functions, Cell Proliferation, and Apoptosis Potential via the Extracellular Signal-Regulated Kinases 1 and 2 Signaling Pathway

Boron is an essential trace element in animals. Appropriate boron supplementation can promote thymus development; however, a high dose of boron can lead to adverse effects and cause toxicity. The influencing mechanism of boron on the animal body remains unclear. In this study, we examined the effect of boron on cytokine expression, thymosin and thymopoietin secretion, antioxidant function, cell proliferation and apoptosis, and extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway in the thymus of rats. We found that supplementation with 10 and 20 mg/L boron to the drinking water significantly elevated levels of interleukin 2 (IL-2), interferon γ (IFN-γ), interleukin 4 (IL-4), and thymosin α1 in the thymus of rats (p < 0.05), increased the number of positive proliferating cell nuclear antigen (PCNA⁺) cells and concentrations of glutathione peroxidase (GSH-Px) and phosphorylated extracellular signal-regulated kinase (p-ERK) (p < 0.05), and promoted mRNA expression of PCNA and ERK1/2 in thymocytes (p < 0.05). However, the number of caspase-3⁺ cells and the expression level of caspase-3 mRNA were reduced (p < 0.05). Supplementation with 40, 80, and 160 mg/L boron had no apparent effect on many of the above indicators. In contrast, supplementation with 480 and 640 mg/L boron had the opposite effect on the above indicators in rats and elevated levels of pro-inflammatory cytokines, such as interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor α (TNF-α) (p < 0.05). Our study showed that supplementation of various doses of boron to the drinking water had a U-shaped dose-effect relationship with thymic cytokine expression, hormone secretion, antioxidant function, cell proliferation, and apoptosis. Specifically, supplementation with 10 and 20 mg/L boron promoted thymocyte proliferation and enhanced thymic functions. However, supplementation with 480 and 640 mg/L boron inhibited thymic functions and increased the number of apoptotic thymocytes, suggesting that the effects of boron on thymic functions may be caused via the ERK1/2 signaling pathway.