Alteration in bone geometric and mechanical properties, histomorphometrical parameters of trabecular bone, articular cartilage, and growth plate in adolescent rats after chronic co-exposure to cadmium and lead in the case of supplementation with green, black, red and white tea

Molecular mechanisms of environmental pollutant-induced cartilage damage: from developmental disorders to osteoarthritis

The objective of the present study was to review the molecular mechanisms of the adverse effects of environmental pollutants on chondrocytes and extracellular matrix (ECM). Existing data demonstrate that both heavy metals, including cadmium (Cd), lead (Pb), and arsenic (As), as well as organic pollutants, including polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCB), bisphenol A, phthalates, polycyclic aromatic hydrocarbons (PAH), pesticides, and certain other organic pollutants that target cartilage ontogeny and functioning. Overall, environmental pollutants reduce chondrocyte viability through the induction apoptosis, senescence, and inflammatory response, resulting in cell death and impaired ECM production. The effects of organic pollutants on chondrocyte development and viability were shown to be mediated by binding to the aryl hydrocarbon receptor (AhR) signaling and modulation of non-coding RNA expression. Adverse effects of pollutant exposures were observed in articular and growth plate chondrocytes. These mechanisms also damage chondrocyte precursors and subsequently hinder cartilage development. In addition, pollutant exposure was shown to impair chondrogenesis by inhibiting the expression of Sox9 and other regulators. Along with altered Runx2 signaling, these effects also contribute to impaired chondrocyte hypertrophy and chondrocyte-to-osteoblast trans-differentiation, resulting in altered endochondral ossification. Several organic pollutants including PCDD/Fs, PCBs and PAHs, were shown to induce transgenerational adverse effects on cartilage development and the resulting skeletal deformities. Despite of epidemiological evidence linking human environmental pollutant exposure to osteoarthritis or other cartilage pathologies, the data on the molecular mechanisms of adverse effects of environmental pollutant exposure on cartilage tissue were obtained from studies in laboratory rodents, fish, or cell cultures and should be carefully extrapolated to humans, although they clearly demonstrate that cartilage should be considered a putative target for environmental pollutant toxicity.

An aqueous extract of Prunella vulgaris L. ameliorates cadmium-induced bone loss by promoting osteogenic differentiation in female rats

Cadmium (Cd) causes bone loss, concerning inhibiting osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Prunella vulgaris L. (PV) has the potential for promoting osteogenic differentiation, but its influence on Cd-induced bone loss is unclear. This study investigated the effect of PV aqueous extract (PVE) on Cd-induced bone loss and its underlying mechanisms. Eight-week-old female SD rats were randomly assigned into four groups and treated for 16 weeks: Control, Cd (50 mg/L of Cd chloride), Cd + PV Low (125 mg/kg bw of PVE), and Cd + PV High (250 mg/kg bw of PVE). PV ameliorated femoral bone loss in Cd-treated rats manifested as increases in bone mineral density, bone volume, trabecular thickness, number, and area, and decreases in trabecular separation. Compared with Cd group, PV-treatment groups had higher serum levels of bone formation markers (ALP, BGP). Additionally, in PV-treatment groups, expressions of bone formation markers (Osterix, Runx2) and molecules involved in osteogenic differentiation signal pathway BMP/Smad (BMP4, Smad1/5/9) in the tibia of rats and isolated rat primary BMSCs were upregulated. These results suggest that PV alleviates Cd-induced bone loss by promoting osteogenic differentiation, which is likely associated with BMP/Smad pathway.

Tannic Acid and Tea Prevents the Accumulation of Lead and Cadmium in the Lungs, Heart and Brain of Adolescent Male Wistar Rats—Possible Therapeutic Option

The protective effect of tannic acid and tea solutions on the lungs, hearts and brains of adolescent Wistar rats exposed to Pb and Cd was studied. Metals were administered with feed (7 mg Cd and 50 mg Pb/kg). Two experiments were carried. Experiment 1 aimed to determine the level of tannic acid (TA), most effectively reducing the adverse impact of Pb and Cd on the organs of adolescent rats (aged 5 weeks, weighing 169.3 ± 14.7 g) during combined exposure. TA was administered with drink (0, 0.5, 1, 1.5, 2 or 2.5% solutions). In Experiment 2, adolescent rats (aged 6 weeks, weighing 210.6 ± 12.1 g) received an aqueous solutions of black, green, red or white teas. TA and teas had a positive effect on reducing the accumulation of Cd in the organs. The results obtained suggest that long-term continuing administration of TA increases its effectiveness as a chelator for Pb. A 2% TA and white tea solution proved to be the most effective. In the analyzed tissues, increased activity of SOD and CAT was recorded as a result of the use of the TA and teas; thus, they can efficiently prevent the prooxidant effect of toxic metals.

Environmental metal exposure and growth to 10 years of age in a longitudinal mother-child cohort in rural Bangladesh

BACKGROUND

Early-life exposure to arsenic (As), cadmium (Cd), and lead (Pb) has been linked to smaller birth and early childhood anthropometry, but little is known beyond the first years in life.

OBJECTIVES

To evaluate the impact of gestational and childhood exposures to As, Cd, and Pb on growth up to 10 years of age.

METHODS

We studied 1530 mother-child dyads from a nested sub-cohort of the MINIMat trial in rural Matlab, Bangladesh. Metal concentrations in maternal erythrocytes during pregnancy and in children's urine at 10y were measured by inductively coupled plasma mass spectroscopy. Child height and weight were measured at 19 occasions from birth until 10y and converted to height-for-age Z-scores (HAZ) and weight-for-age Z-scores (WAZ). Associations between log₂-transformed metal concentrations and growth parameters were assessed with multivariable-adjusted regression models.

RESULTS

Children's concurrent urinary Cd (median 0.24 µg/L), reflecting long-term exposure, was inversely associated with WAZ (B: -0.072; 95% confidence interval (CI): -0.12, -0.020; p = 0.007), and possibly HAZ (B: -0.046; 95% CI: -0.096, 0.0014; p = 0.057), at 10y. The association with WAZ was stronger in boys than in girls. Maternal erythrocyte Cd (median 0.90 µg/kg) during pregnancy was inversely associated with WAZ during childhood only in boys (B: -0.071, 95% CI: -0.14, -0.0047, p = 0.036). Concurrent urinary Pb (median 1.6 µg/L) was inversely associated with WAZ (B: -0.084; 95% CI: -0.16, -0.0085; p = 0.029) and HAZ (B: -0.087; 95% CI: -0.15, -0.021; p = 0.010) in boys, but not in girls. Neither gestational nor childhood As exposure (median maternal erythrocyte As 4.3 µg/kg and children's urinary As 57 µg/L) was associated with growth up to 10y.

CONCLUSIONS

While all effect estimates were small, environmental exposure to Cd and Pb is common and impaired growth is of public health concern, especially for children already at risk of reduced growth due to malnutrition. Gender differences in susceptibility need further investigation.

A Comprehensive Insight on the Health Benefits and Phytoconstituents of Camellia sinensis and Recent Approaches for Its Quality Control

Tea, Camellia sinensis, which belongs to the family Theaceae, is a shrub or evergreen tree up to 16 m in height. Green tea is very popular because of its marked health benefits comprising its anticancer, anti-oxidant, and antimicrobial activities, as well as its effectiveness in reducing body weight. Additionally, it was recognized by Chinese people as an effective traditional drink required for the prophylaxis against many health ailments. This is due to the complex chemical composition of green tea, which comprises different classes of chemical compounds, such as polyphenols, alkaloids, proteins, minerals, vitamins, amino acids, and others. The beneficial health effects of green tea ultimately led to its great consumption and increase its liability to be adulterated by either low-quality or non-green tea products with concomitant decrease in activity. Thus, in this review, green tea was selected to highlight its health benefits and phytoconstituents, as well as recent approaches for its quality-control monitoring that guarantee its incorporation in many pharmaceutical industries. More research is needed to find out other more biological activities, active constituents, and other simple and cheap techniques for its quality assurance that ascertain the prevention of its adulteration.

Bone Homeostasis in Experimental Fumonisins Intoxication of Rats

Fumonisins are strongly toxic metabolites of Fusarium proliferatum and Fusarium verticillioides commonly present in corn-based feed. The aim of the study was to evaluate bone homeostasis in experimental fumonisins B1 and B2 intoxication of rats, a vertebrate animal model of toxicological studies, as still little is known about the possible disturbing effect of fumonisins on bone homeostasis. Adolescent (5-week-old) male Wistar rats were randomly assigned into a control group and a group FB intoxicated with fumonisins by daily intragastric administration of fumonisins at the dose of 90 mg/kg of body weight per animal in the FB group for 21 days. The fumonisin intoxication did not affect body and bone mass, although the mechanical and geometric properties were decreased in fumonisin-intoxicated rats. Bone volumetric and mineral density did not differ between groups, but bone mineral content and bone ash percentage was lower in the FB group. Detailed analysis showed that Ca, Cu, Fe, Mn, Sr, and Zn bone content significantly decreased in fumonisin intoxicated rats and the alterations in structure of bone mineral phase (reduction of the apatite-bone crystals size) were noted. While the negative structural alterations in growth plate and articular cartilages were also observed, fumonisin intoxication improved histomorphometrical parameters of trabecular bone. Concluding, the dose of fumonisins used in the present study caused hepatotoxic effect, which was sufficient to trigger the disturbance in mineral homeostasis resulting in altered bone metabolism and decreased mechanical endurance.

The effects of lead on the development of somites in chick embryos (Gallus gallus domesticus) under in vitro conditions: a histological study

Lead (Pb) is one of the most abundant toxic metals in the environment that can cause a variety of harmful effects. During embryonic development of vertebrates, somites are temporary organs that give rise to skeletal muscle, cartilage, tendon, endothelial cells, and dermis. In this study, we investigated the effects of lead on the development of somites and their derivatives in chick embryos under in vitro conditions. For this propose, fertilized eggs of Gallus gallus domesticus were incubated until they reached the stage of 15-20 somites. The somites and notochord were isolated and treated with different concentrations of lead acetate (500, 1000, 2000, and 4000 ng ml-1) for 72 h. Our results indicated that high concentrations of lead reduced the nucleus diameter, reduced the synthesis of collagen, inhibited the formation of the cartilage matrix in somite cells, and disturbed the formation and order of myotubes. In conclusion, the results of the current study for the first time indicated the disturbing effects of lead on the development of somites in the chick embryo. Our results revealed that lead disturbed the development of somites in the chick embryo, which suggested that at high concentrations it can cause a serious mortal danger to life.

The effect of cadmium exposition on the structure and mechanical properties of rat incisors

Alterations in the structure and mechanical properties of teeth in adult Wistar rats exposed to cadmium were investigated. Analyses were conducted on two sets of incisors from female and male specimens, that were intoxicated with cadmium (n = 12) or belonged to the control (n = 12). The cadmium group was administered with CdCl2 dissolved in drinking water with a dose of 4mg/kgbw for 10 weeks. The oral intake of cadmium by adult rats led to the range of structural changes in enamel morphology and its mechanical features. A significant increase of cadmium levels in the teeth in comparison to the control, a slight shift in the colour and reduction of pigmented enamel length, higher surface irregularity, a decrease of hydroxyapatite crystals size in the c-axis and simultaneous increase in pigmented enamel hardness were observed. The extent of these changes was sex-dependent and was more pronounced in males.

Wnt/β-Catenin Pathway Is Involved in Cadmium-Induced Inhibition of Osteoblast Differentiation of Bone Marrow Mesenchymal Stem Cells

Cadmium is a common environmental pollutant that causes bone damage. However, the effects of cadmium on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs) and its mechanism of action in this process are unclear. Here, we determined the effects of cadmium chloride (CdCl₂) on the osteogenic differentiation of BMMSCs and the potential mechanism involved in this process. As determined in the present investigation, CdCl₂, in a concentration-dependent manner, affected the viability of BMMSCs and their cytoskeletons. Exposure to 0.1 or 0.2 µM CdCl₂ inhibited osteogenic differentiation of BMMSCs, which was reflected in the down-regulation of osteoblast-related genes (ALP, OCN, Runx2, OSX, and OPN); in suppression of the protein expression of alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2); and in decreased ALP activity and capacity for mineralization. Moreover, mRNA microarray was performed to determine the roles of these factors in BMMSCs treated with CdCl₂ in comparison to control BMMSCs. As determined with the microarrays, the Wingless-type (Wnt), mothers against decapentaplegic and the C. elegans gene Sam (SMAD), and Janus kinase-Signal Transducers and Activators of Transcription (JAK-STAT) signaling pathways were involved in the effects caused by CdCl₂. Moreover, during differentiation, the protein levels of Wnt3a, β-catenin, lymphoid enhancer factor 1 (LEF1), and T-cell factor 1 (TCF1) were reduced by CdCl₂. The current research shows that CdCl₂ suppresses the osteogenesis of BMMSCs via inhibiting the Wnt/β-catenin pathway. The results establish a previously unknown mechanism for bone injury induced by CdCl₂.

Analysis of bone osteometry, mineralization, mechanical and histomorphometrical properties of tibiotarsus in broiler chickens demonstrates a influence of dietary chickpea seeds (Cicer arietinum L.) inclusion as a primary protein source

This study was focused on analyzing the effects of dietary inclusion of raw chickpea seed as a replacement of soybean meal as a primary protein source on bone structure in broiler chickens. Broiler chickens (n = 160) received in their diet either soybean meal (SBM) or raw chickpea seeds (CPS) as a primary protein source throughout the whole rearing period (n = 80 in each group). On the 42th day randomly selected chickens from each group (n = 8) were slaughtered. Collected tibiotarsus were subjected to examination of the biomechanical characteristics of bone mid-diaphysis, microstructure of the growth plate and articular cartilages; the analysis of mineral content and crystallinity of mineral phase, and the measurements of thermal stability of collagen in hyaline cartilage were also carried out. The inclusion of chickpea seeds resulted in increase of bone osteometric parameters (weight, length and mid-diaphysis cross-sectional area) and mechanical endurance (yield load, ultimate load, stiffness, Young modulus). However, when loads were adjusted to bone shape (yield and ultimate stress) both groups did not differ. Mineral density determined by means of densitometric measurements did not differ between groups, however the detailed analysis revealed the differences in the macro- and microelements composition. The results of FT-IR and XRD analyses showed no effect of diet type on mineral phase crystallinity and hydroxyapatite nanocrystallites size. In trabecular bone, the increase of real bone volume (BV/TV) and number of trabeculae was observed in the CPS group. Total thickness of articular cartilage was the same in both groups, save the transitional zone, which was thicker in the SBM group. The total thickness of the growth plate cartilage was significantly increased in the CPS group. The area of the most intense presence of proteoglycans was wider in the SBM group. The structural analysis of fibrous components of bone revealed the increase of fraction of thin, immature collagen content in articular cartilage, trabeculae and compact bone in the CPS group. The dietary inclusion of CPS affected the thermal stability of collagen, as decrease of net denaturation enthalpy was observed. This study showed a beneficial effect of CPS on the skeletal development, improving the overall bone development and the microarchitecture of cancellous bone. It suggests that CPS can be a promising replacement for SBM in broilers feeding in the aspect of animal welfare related to the development of the skeletal system.

Protective effect of tea against lead and cadmium-induced oxidative stress-a review

Exposure to Cd and Pb reduces the activity of antioxidant enzymes, which points to a decrease in the antioxidant potential of the body as a result of supplying factors which enhance cellular oxidation processes. Man is exposed to the effects of toxic metals because they are present in the environment, including in food. Since no effective ways to reduce the concentrations of Cd an Pb in food exist, studies are undertaken to develop methods of reducing their toxic effect on the body through chelating these metals using nutrients (which reduces their absorption by tissues) or increasing the oxidative capacity of the body (which decreases the possibility of inducing oxidative damage to internal organs). Studies performed on laboratory animals have shown that the use of tea infusions fulfil both functions.

White Tea is More Effective in Preservation of Bone Loss in Adult Rats Co-Exposed to Lead and Cadmium Compared to Black, Red or Green Tea

Lead (Pb) and cadmium (Cd) are toxic metals occurring commonly in the human environment that show mutagenic, genotoxic and carcinogenic effects. Dietary components could prevent heavy metals intoxication by reducing their accumulation in the body. The purpose of the study was to check possible protective effect of regular consumption of white, black, red, or green tea on bone metabolism during long-term exposure to Pb and Cd in adult rats. The 12 week-long exposure to Pb and Cd (50 mg Pb and 7 mg Cd/kg of the diet) in a rat model was studied. Twelve-week-old adult male Wistar rats were randomly divided into a negative control group (Pb and Cd exposure without tea), a control (without Pb and Cd and teas), and groups co-exposed to Pb and Cd and supplemented with green, red, black, or white tea (n=12 each group). The experiment lasted for 12 weeks. The co-exposure to Pb and Cd led to the increase of bone resorption depending on the tea treatment, which was confirmed by the mechanical testing and histomorphometrical examination of cancellous bone. Pb and Cd influenced mechanical strength, reduced the densitometric and geometric parameters and the thickness of growth plate and articular cartilages. Concluding, white tea exerted the best protective effect on bone tissue and hyaline cartilage against heavy metal action.

Is the consumption of snail meat actually healthy? An analysis of the osteotropic influence of snail meat as a sole source of protein in growing rats

The study was aimed at determining the osteotropic effects of diets containing snail meat as a sole protein source. In our experiment, we tested three different diets incorporating snail meat originating from Helix pomatia (HP), Cornu.aspesa maxima (CAM) and Cornu.aspersum aspersum (CAA) and compared these to a control diet (CON) in which casein was the source of protein. In all diets, the protein content amounted to 10%, as calculated on a dry weight basis. In the study, forty male Wistar rats with an initial body mass of 50 ± 2 g were randomly placed within the control and three experimental groups. After 28 days of experimental feeding, the rats were sacrificed, and the body mass, total skeletal density and body composition were recorded. Moreover, blood serum (osteocalcin, CTX) and isolated tibia (pQCT, DXA, 3D micro-CT, 3-point bending test) were stored for further analysis. The results reveal that a diet incorporating snail meat significantly decreased BMC (bone mineral content), as well as area of total skeleton and isolated tibia, and was without influence on BMD (bone mineral density). Furthermore, the 3D micro-CT analysis of trabecular compartment documented a reduced Tb.Th (trabecular thickness), as well as Tb.N (trabecular number), and an increased Tb.Sp (trabecular separation). Beyond the aforementioned, the snail-based diets had an influence upon the architectonical properties of the tibia-decreasing its resistance to mechanical loading. Finally, snail meat, when used as an alone source of protein, negatively influenced the metabolism of the bone tissue in growing animals-making bone smaller and weaker.

Dose-Dependent Influence of Dietary Cu-Glycine Complex on Bone and Hyaline Cartilage Development in Adolescent Rats

Administration of the amino acid copper (Cu) complex ensures higher Cu bioavailability through enhanced absorption from intestine and decreases the dietary Cu level, compared to the recommended Cu dose. The objective of this study was to investigate the effect of Cu-low diet on the bone development in adolescent rats. Male rats at the age of 6 weeks were used in the 12-week experiment. The control diet provided the required Cu level from sulfate (S-Cu) and other diets were supplemented with Cu as a glycine complex (Cu-Gly) at 25%, 50%, 75%, and 100% of daily requirement. After the 12-week treatment, rats from the Cu-Gly100 group were heavier, compared to the other groups. The copper and calcium plasma and bone concentrations of the rats in the groups treated with the organic form of Cu (irrespective of its dose) was similar to the control values noted in the rats administered with S-Cu. A decrease in the femur weight and length was observed in the Cu-Gly75 and Cu-Gly50 groups. Cu-Gly increased the cross section area, mean relative wall thickness, and cortical index only in the Cu-Gly75 group. A decrease in the ultimate strength, elastic stress, and ultimate stress was noted in the Cu-Gly100 and Cu-Gly75 groups. In the Cu-Gly50 group, a decrease in the ultimate stress and an increase in the maximal elastic strength and bending moment were noted. Adolescent rats treated with Cu-Gly at a Cu-deficient level exhibited a dose-dependent strongly osteoporotic cancellous bone. Lower proteoglycan content was found in groups fed the Cu-low diet. In the control rats supplemented with S-Cu, there was no evident gradient in safranin O staining. It is difficult to indicate which dose of the Cu-Gly complex among the investigated Cu-poor diet exerted a positive effect on bone metabolism. It appears that the use of this Cu-Gly complex at a significantly reduced dose than S-Cu at the recommended dose did not inhibit the development of bone and hyaline cartilage in adolescent rats.

Emodin suppresses cadmium-induced osteoporosis by inhibiting osteoclast formation

Environmental level of cadmium (Cd) exposure can induce bone loss. Emodin, a naturally compound found in Asian herbal medicines, could influence osteoblast/osteoclast differentiation. However, the effects of emodin on Cd-induced bone damage are not clarified. The aim of this study was to investigate the role of emodin on Cd-induced osteoporosis. Sprague-Dawley male rats were divided into three groups which were given 0mg/L, 50mg Cd/L and 50mg Cd/L plus emodin (50mg/kg body weight). Bone histological investigation, microCT analysis, metabolic biomarker determination and immunohistochemical staining were performed at the 12th week. The bone mass and bone microstructure index of rats treated with Cd were obviously lower than in control. Cd markedly enhanced the osteoclast formation compared with control. Emodin significantly abolished the Cd-induced bone microstructure damage (p<0.05), osteoclast formation and increase of tartrate-resistant acid phosphatase 5b level (p<0.05). Our data further showed that emodin attenuated the Cd-induced inhibition of osteoprotegerin expression and stimulation of receptor activator for nuclear factor-κ B ligand expression. Our data show that emodin suppresses the Cd-induced osteoporosis by inhibiting osteoclast formation.

Effects of Olive Leaf and Marigold Extracts on the Utilization of Nutrients and on Bone Mineralization using Two Different Oil Sources in Broilers

The aim of this study was to investigate the effects of olive leaf and marigold extracts on the apparent total tract digestibility (ATTD) of the principal nutrients and energy, as well as on mineral utilization (Ca, P, Mg, Mn, Fe, Cu and Zn) in relation to bone characteristics in broilers fed walnut- or linseed oil-supplemented diets. Thirty-six 12-day-old commercial broilers Ross 308 were reared in metabolic cages, assigned to one of the six dietary treatments (3 × 2 factorial design): three supplements (not supplemented, olive leaf extract, or marigold extract), and two oils (walnut or linseed oil). The results showed that the marigold extract reduced Zn and P balances and tended to lower the balance of ash and Mg, and the ATTD of Zn and Mg. Diets with linseed oil increased the ATTD of acid detergent fiber and reduced the ATTD of the organic residue and Cu. No differences in the bone characteristics of tibia were observed between treatments. These results indicated that the inclusion of marigold extract had a negative effect on the Zn and P balance, and that neither extract had any major effect on the digestion and utilization of energy and other investigated nutrients, or on bone mineralization, irrespective of the oil source included in the diet.

The Influence of the Dietary Cu-Glycine Complex on the Histomorphology of Cancellous Bone, Articular Cartilage, and Growth Plate as well as Bone Mechanical and Geometric Parameters Is Dose Dependent

Copper (Cu) is required for all basic biochemical and physiological processes. The objective of this study was to compare the effect of two different chemical forms (sulfates and glycinate chelates also below the recommended dose) of Cu administered to adult rats on the biomechanical and morphometric properties of femur. Male rats at the age of 12 weeks were used in the 12-week experiment. The control diet provided the required Cu level from sulfate (S-Cu), and the other diets were supplemented with Cu-glycine complex. The Cu-Gly-treatment, irrespective of its concentration, did not influence the bone mass and length. The Cu-Gly-treatment in 100 and 75% of daily demand increased mechanical endurance. The Cu-Gly-treatment (regardless of its concentration) increased the real bone volume in epiphysis and decreased the total thickness and zone I of the articular cartilage compared to the control group supplemented with S-Cu. The Cu-Gly-treatment enhanced the content of proteoglycans (except the OG50 group). Dietary Cu given to adult rats in the Cu-Gly complex covering the daily demand in 75% exerted a positive effect on bone metabolism and appeared to be the most effective among the investigated doses of the organic form.