Structural changes in femoral bone tissue of rats after subchronic peroral exposure to selenium

Toxicity of repeated oral intake of organic selenium, inorganic selenium, and selenium nanoparticles: A review

BACKGROUND

To protect from toxicity at supra-essential doses of selenium, it is important to determine dose levels at which adverse effects occur.

METHODS

We identified relevant literature on the repeated dosage of selenium and extracted dose descriptors on reported endpoints, except on genotoxicity/carcinogenicity.

RESULTS

Selenium forms with toxicological data were organic ones: selenomethionine, selenocystine/selenocysteine; and inorganic ones, including selenite (SeO₃^2-), selenate (SeO₄^2-), selenium sulphide (SeS₂), selenide (Se^2-) and selenium nanoparticles. Clinical signs of selenium toxicity in humans include a garlicky-smelling breath, hair loss, and nail changes. One human study showed increased mortality following daily ingestion of 300 µg Se per day for 5 years, equal to a lowest-observed-adverse-effect level (LOAEL) of ∼4.3 µg/kg bw/days. The corresponding no-observed-adverse-effect level (NOAEL) was ∼2.9 µg Se/kg bw/day. One study reported an increased risk of type 2 diabetes after ∼2.9 µg Se/kg bw/day, but other studies with similar doses found no increases in mortality or incidence of type 2 diabetes. NOAELs on affected body weight in animal studies were 0.24-1.2 mg Se/kg bw/day. Other endpoints of selenium toxicity in animals include hepatotoxicity with a NOAEL as low as 2 µg/kg bw/day in rats, as well as gastrointestinal, cardiovascular, and reproductive toxicities with NOAELs of 0.6 (gastrointestinal), 0.08, and 0.4 (cardiovascular) and ≥ 0.04 mg Se/kg bw/day (reproductive), respectively.

CONCLUSIONS

Dose descriptors describing selenium toxicity were as low as 2-3 µg Se/kg bw/day.

The Effects of Prolonged Treatment with Cemtirestat on Bone Parameters Reflecting Bone Quality in Non-Diabetic and Streptozotocin-Induced Diabetic Rats

Cemtirestat, a bifunctional drug acting as an aldose reductase inhibitor with antioxidant ability, is considered a promising candidate for the treatment of diabetic neuropathy. Our study firstly examined the effects of prolonged cemtirestat treatment on bone parameters reflecting bone quality in non-diabetic rats and rats with streptozotocin (STZ)-induced diabetes. Experimental animals were assigned to four groups: non-diabetic rats, non-diabetic rats treated with cemtirestat, diabetic rats, and diabetic rats treated with cemtirestat. Higher levels of plasma glucose, triglycerides, cholesterol, glycated hemoglobin, magnesium, reduced femoral weight and length, bone mineral density and content, parameters characterizing trabecular bone mass and microarchitecture, cortical microarchitecture and geometry, and bone mechanical properties were determined in STZ-induced diabetic versus non-diabetic rats. Treatment with cemtirestat did not affect all aforementioned parameters in non-diabetic animals, suggesting that this drug is safe. In diabetic rats, cemtirestat supplementation reduced plasma triglyceride levels, increased the Haversian canal area and slightly, but insignificantly, improved bone mineral content. Nevertheless, the insufficient effect of cemtirestat treatment on diabetic bone disease does not support its use in the therapy of this complication of type 1 diabetes mellitus.

The Localized Ionic Microenvironment in Bone Modelling/Remodelling: A Potential Guide for the Design of Biomaterials for Bone Tissue Engineering

Bone is capable of adjusting size, shape, and quality to maintain its strength, toughness, and stiffness and to meet different needs of the body through continuous remodeling. The balance of bone homeostasis is orchestrated by interactions among different types of cells (mainly osteoblasts and osteoclasts), extracellular matrix, the surrounding biological milieus, and waste products from cell metabolisms. Inorganic ions liberated into the localized microenvironment during bone matrix degradation not only form apatite crystals as components or enter blood circulation to meet other bodily needs but also alter cellular activities as molecular modulators. The osteoinductive potential of inorganic motifs of bone has been gradually understood since the last century. Still, few have considered the naturally generated ionic microenvironment's biological roles in bone remodeling. It is believed that a better understanding of the naturally balanced ionic microenvironment during bone remodeling can facilitate future biomaterial design for bone tissue engineering in terms of the modulatory roles of the ionic environment in the regenerative process.

Bee Bread Can Alleviate Lipid Abnormalities and Impaired Bone Morphology in Obese Zucker Diabetic Rats

This study examined for the first time whether bee bread (BB, consisting of monofloral rape bee pollen) could alleviate lipid derangements and reduced bone quality in Zucker diabetic fatty (ZDF) rats, which are considered an appropriate animal model for type 2 diabetes mellitus (T2DM) investigation. Adult ZDF rats were segregated into four groups: lean non-diabetic rats (L group), obese diabetic rats untreated (C group), and those treated with the BB at two doses (500 and 700 mg/kg body weight, respectively, B1 and B2 groups) for 10 weeks. Significantly reduced levels of total cholesterol and triglyceride were recorded in the B2 group versus the C group. In both BB-treated groups, significantly increased relative volume of trabecular bone and trabecular thickness, enhanced density of secondary osteons, accelerated periosteal bone apposition, and improved blood flow were observed. A positive effect of higher dose of BB on femoral weight and cortical bone thickness was also demonstrated. Our results suggest a promising potential of BB to ameliorate T2DM-related complications associated with lipid and bone damages.

The effects of eggshell calcium (Biomin H® ) and its combinations with alfacalcidol (1α-hydroxyvitamin D3) and menaquinone-7 (vitamin K2) on ovariectomy-induced bone loss in a rat model of osteoporosis

The purpose of this study was to investigate the impact of eggshell calcium (Biomin H® dietary supplement) and its combinations with alfacalcidol (1α-hydroxyvitamin D3 ) and menaquinone-7 (vitamin K2 ) on ovariectomy-induced bone loss in rats. Adult female rats (n = 48) were divided into 6 groups of 8 individuals each: sham-operated rats (SHAM); ovariectomized (OVX) rats untreated; OVX rats treated with Biomin H® (BIO); OVX rats simultaneously receiving Biomin H® , vitamin D3 (BIO + D3 ); OVX rats simultaneously treated with Biomin H® , vitamin K2 (BIO + K2 ) and OVX rats treated with Biomin H® , vitamin D3 , vitamin K2 (BIO + D3  + K2 ) during 8 weeks. Biochemical parameters, bone mineral density (BMD), bone mineral content (BMC) and femoral bone microstructure were determined. Plasma calcium and phosphate were increased in BIO + D3 and BIO + D3  + K2 groups as compared to OVX. Alkaline phosphatase was elevated in OVX, BIO versus SHAM, BIO + D3  + K2 groups. When compared to OVX group, decreased urine deoxypyridinoline was observed in all treated groups and femoral BMD, BMC were higher in BIO, BIO + D3 , BIO + D3  + K2 groups. The BIO + K2 rats had similar densitometrical values than OVX individuals. Microcomputed tomography revealed increased trabecular relative bone volume (due to an increase in trabecular number) in BIO + D3 , BIO + D3  + K2 as compared to OVX. The higher relative bone volume in BIO + D3 , BIO + D3  + K2 groups was also accompanied by an increase in bone surface. In the cortical bone, an enhanced periosteal bone apposition was identified in BIO, BIO + D3 , BIO + K2 , BIO + D3  + K2 groups. The rats from BIO + D3  + K2 group had a higher area of primary osteon's vascular canals. In BIO + D3 , BIO + K2 , BIO + D3  + K2 groups, an increased area of secondary osteons was determined in comparison with OVX. Our results indicate the beneficial effect of triple application of Biomin H® , vitamin D3 , vitamin K2 , as well as simultaneous administration of Biomin H® , vitamin D3 on the inhibition of ovariectomy-induced bone loss in a rat model of osteoporosis.

Arsenic, cadmium, and selenium exposures and bone mineral density-related endpoints: The HORTEGA study

BACKGROUND AND OBJECTIVES

Experimental data suggest that trace elements, such as arsenic (As), cadmium (Cd), and selenium (Se) can influence the bone remodeling process. We evaluated the cross-sectional association between As, Cd, and Se biomarkers with bone mineral density (BMD) measured at the calcaneus, in a representative sample of a general population from Spain. As secondary analyses we evaluated the associations of interest in subgroups defined by well-established BMD determinants, and also conducted prospective analysis of osteoporosis-related incident bone fractures restricted to participants older than 50 years-old.

METHODS

In N = 1365 Hortega Study participants >20 years-old, urine As and Cd were measured by inductively coupled-plasma mass spectrometry (ICPMS); plasma Se was measured by atomic absorption spectrometry (AAS) with graphite furnace; and BMD at the calcaneus was measured using the Peripheral Instaneuous X-ray Imaging system (PIXI). As levels were corrected for arsenobetaine (Asb) to account for inorganic As exposure.

RESULTS

The median of total urine As, Asb-corrected urine As, urine Cd, and plasma Se was 61.3, 6.53 and 0.39 μg/g creatinine, and 84.9 μg/L, respectively. In cross-sectional analysis, urine As and Cd were not associated with reduced BMD (T-score < -1 SD). We observed a non-linear dose-response of Se and reduced BMD, showing an inverse association below ~105 μg/L, which became increasingly positive above ~105 μg/L. The evaluated subgroups did not show differential associations. In prospective analysis, while we also observed a U-shape dose-response of Se with the incidence of osteoporosis-related bone fractures, the positive association above ~105 μg/L was markedly stronger, compared to the cross-sectional analysis.

CONCLUSIONS

Our results support that Se, but not As and Cd, was associated to BMD-related disease. The association of Se and BMD-related disease was non-linear, including a strong positive association with osteoporosis-related bone fractures risk at the higher Se exposure range. Considering the substantial burden of bone loss in elderly populations, additional large prospective studies are needed to confirm the relevance of our findings to bone loss prevention in the population depending on Se exposure levels.

Cornelian Cherry Pulp Has Beneficial Impact on Dyslipidemia and Reduced Bone Quality in Zucker Diabetic Fatty Rats

Cornelian cherry (Cornus mas L.) is a medicinal plant with a range of biological features. It is often used as a nutritional supplement in the treatment of diabetes mellitus. Our study was aimed to first investigate the effects of Cornelian cherry pulp on bone quality parameters in Zucker diabetic fatty (ZDF) rats. Moreover, lipid-lowering properties of this fruit were also evaluated. Adult rats (n = 28) were assigned into four groups of seven individuals each: L group (non-diabetic lean rats), C group (diabetic obese rats), and E1 and E2 groups (diabetic obese rats receiving 500 and 1000 mg/kg body weight of Cornelian cherry pulp, respectively, for 10 weeks). Significantly lower levels of triglyceride, total cholesterol and alkaline phosphatase activity were determined in the E2 group versus the C group. A higher dose of Cornus mas also had a beneficial impact on femoral weight, cortical bone thickness, relative volume of trabecular bone and trabecular thickness. We observed elevated density of Haversian systems and accelerated periosteal bone apposition in both treated groups (E1 and E2). Our results clearly demonstrate that Cornelian cherry pulp has a favorable effect on lipid disorder and impaired bone quality consistent with type 2 diabetes mellitus in a suitable animal model.

Antagonistic Impact of Acrylamide and Ethanol on Biochemical and Morphological Parameters Consistent with Bone Health in Mice

Simple Summary

Alcohol consumption, the drinking of beverages containing ethanol, represents a growing problem worldwide. Alcohol intake is often combined with an improper diet based on highly processed starch products that are rich in acrylamide. Both acrylamide and alcohol have a harmful impact on bone health. We previously demonstrated that adverse effects of ethanol on cortical bone structure were partly reduced by a relatively high dose of acrylamide in mice after one remodelling cycle. The present research was designated to reveal whether the antagonistic impact of both aforementioned toxins can also be achieved using a lower dose of acrylamide. According to our results, individual administrations of acrylamide and ethanol had adverse impacts on biochemical and morphological parameters consistent with bone health in mice. However, the most detrimental effects of ethanol were again alleviated by acrylamide at the dose used in this study.

Abstract

The aim of present study was to verify antagonistic effect of acrylamide (AA) and ethanol (Et) on bone quality parameters. Adult mice (n = 20) were segregated into four groups following 2 weeks administration of toxins: group E1, which received AA (20 mg/kg body weight daily); group E2, which received 15% Et (1.7 g 100% Et/kg body weight daily); group E12, which received simultaneously both toxins; and a control group. An insignificant impact of individual applications of AA, Et or their simultaneous supplementation on the total body weight of mice and the length and weight of their femoral bones was identified. In group E1, higher levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), a decreased level of glutathione (GSH) and elevated endocortical bone remodelling were determined. A significantly lower relative volume of cortical bone, bone mineral density (BMD), elevated endocortical bone remodelling and cortical porosity, higher levels of ALT, AST, lower values for total proteins (TP), GSH, alkaline phosphatase (ALP), calcium, and phosphorus were recorded in group E2. In the mice from group E12, the highest endocortical bone remodelling, decreased values for BMD, TP, GSH and ALP and increased levels of ALT and AST were found. Our findings confirmed the antagonistic impact of AA and Et at doses used in this study on biochemical and morphological parameters consistent with bone health in an animal model.

Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians

The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.

Single and simultaneous effects of acrylamide and ethanol on bone microstructure of mice after one remodeling cycle

Background

This study aimed to examine femoral bone microstructure of mice after single and simultaneous administration to acrylamide and ethanol since both substances are often consumed separately and/or together by humans. Interactive effects of these toxins were analysed after one remodeling cycle.

Methods

Twenty clinically healthy adult mice were randomly divided into four groups following 2 weeks administration of toxins: A group - mice were fed with acrylamide (40 mg/kg bw); E group - mice were ethanol-fed (15% ethanol); AE group - mice were simultaneously fed with both toxins, and a C group – control (without acrylamide and/or ethanol supplementation). Generally, 2D and 3D imaging methods were used to determine cortical and trabecular bone tissues microstructure. Biochemical analyses of plasma parameters were also realized using commercially available ELISA tests and spectrophotometrically.

Results

Single and simultaneous exposure to acrylamide and ethanol affected only cortical bone microstructure. No significant changes in trabecular bone morphometry were detected among all groups. In mice from the A group, increased endocortical remodeling associated with a higher level of serum calcium and vasoconstriction of primary osteon’s vascular canals (POVC) were identified. On the contrary, increased cortical porosity consistent with a decreased relative bone volume, bone mineral density (BMD) and lower levels of alkaline phosphatase (ALP), glutathione (GSH), calcium in plasma and also with vasodilation of POVC were observed in the E group. In the AE group, the highest density of secondary osteons associated with a lower BMD and decreased levels of ALP, GSH were documented. The parameters of POVC and Haversian canals approximated to the C group. In addition, single and simultaneous exposure to both toxins caused liver disease consistent with a higher values of alanine aminotransferase (ALT), aspartate aminotransferase (AST) in plasma of all experimental groups.

Conclusions

Single administration to acrylamide and ethanol had negative effects on cortical bone structure of mice after one remodeling cycle. However, we identified possible antagonistic impact of these toxins on the structure of the cortical bone.

Bone microstructure of mice after prolonged taurine treatment

Taurine, a sulphur - containing amino acid, has been termed a functional nutrient. Its synthetic form is a common ingredient in supplements and energy drinks. There is no information concerning taurine impact on bone microstructure after prolonged supplemental use. Also, differences in bone parameters of mice following taurine exposure are unknown. In this study, a detailed microstructure of compact and trabecular bone tissues of mice subchronically exposed to taurine was determined. Animals (n=12) were segregated into three groups: E1 group - mice received 20 mg/kg b.w. of taurine per day during 8 weeks; E2 group - mice were fed by taurine at a dose of 40 mg/kg b.w. for 8 weeks and a control (C) group. Decreased density of secondary osteons, increased sizes of primary osteon's vascular canals (P<0.05) were observed in taurine - treated animals. Cortical bone thickness, trabecular thickness were decreased (P<0.05) in E1 group, and relative volume of trabecular bone was lower (P<0.05) in E2 group as compared to C group. According to our results, prolonged taurine exposure at the doses used in this study can negatively affect both compact and trabecular bone tissues microstructure.

Changes in the microstructure of compact and trabecular bone tissues of mice subchronically exposed to alcohol

BACKGROUND

Alcohol is one of the most commonly consumed neurotoxins by humans. Its negative effect on bone health is known for a long time. However, its impact on qualitative and quantitative 2D characteristics of the compact bone is still unclear. Therefore, the aim of this study was to investigate in detail the effects of subchronic alcohol exposure on compact and trabecular bone tissues microstructure of laboratory mice using 2D and 3D imaging methods. Ten clinically healthy 12 weeks-old mice (males) were randomly divided into two groups. Animals from experimental group (group E; n = 5) drank a solution composed of 15% ethanol and water (1.7 g 100% ethanol kg-1 b.w. per day) for 8 weeks, while those from control group (group C; n = 5) drank only water.

RESULTS

Subchronic exposure to alcohol leads to several changes in qualitative 2D characteristics of the compact bone such as the presence of primary vascular radial bone tissue in pars anterior of endosteal border and a higher number of resorption lacunae (five times more) in the middle part of substantia compacta. Morphometrical 2D evaluations of the compact bone showed significantly increased sizes of primary osteons' vascular canals (p < 0.05) in mice from the experimental group (E group). Sizes of Haversian canals and secondary osteons were not affected by alcohol consumption. In mice from the E group, significantly lower values for relative bone volume and bone mineral density of the compact bone were observed. In the trabecular bone, decreased values for bone volume, trabecular number, trabecular thickness and bone surface (p < 0.05) were documented.

CONCLUSIONS

Alcohol decreased not only bone volume and density of the compact bone, but it also reduced trabecular bone volume and leads to trabecular thinning. It caused vasodilation of primary osteons' vascular canals and increased porosity in the compact bone.

Subacute exposure to alcohol in relation to bone microstructure of mice

Our study aimed to investigate subacute exposure to alcohol in relation to bone microstructure of mice. Animals from experimental (E) group drank a solution composed of 15 % ethanol and water for 14 days (one remodeling cycle), while those from control (C) group drank only water. In the compact bone of E group, decreased bone formation and increased porosity were observed which corresponds with lower levels of serum alkaline phosphatase and glutathione. Alcohol significantly increased sizes of primary osteon's vascular canals and decreased those of secondary osteons, Haversian canals. Relative bone volume, bone mineral density (BMD), relative bone volume without marrow cavity were also lower in E group. On the contrary, trabecular bone microstructure did not differ significantly between E and C groups. Liver function test showed higher levels of alanine aminotransferase, aspartate aminotransferase in alcohol-fed mice. Serum calcium, phosphate were significantly lower in E group. According to our study, only changes in compact bone microstructure of mice following one remodeling cycle were observed due to both direct and indirect effects of alcohol.

Carrageenan based hydrogels for drug delivery, tissue engineering and wound healing

Carrageenan is a class of naturally occurring sulphated polysaccharides, which is currently a promising candidate in tissue engineering and regenerative medicine as it resemblances native glycosaminoglycans. From pharmaceutical drug formulations to tissue engineered scaffolds, carrageenan has broad range of applications. Here we provide an overview of developing various forms of carrageenan based hydrogels. We focus on how these fabrication processes has an effect on physiochemical properties of the hydrogel. We outline the application of these hydrogels not only pertaining to sustained drug release but also their application in bone and cartilage tissue engineering as well as in wound healing and antimicrobial formulations. Administration of these hydrogels through various routes for drug delivery applications has been critically reviewed. Finally, we conclude by summarizing the current and future outlook that promotes the seaweed-derived polysaccharide as versatile, promising biomaterial for a variety of bioengineering applications.

Selenium, cadmium and diazinon insecticide in tissues of rats after peroral exposure

The concentrations of selenium (Se), cadmium (Cd) and diazinon (DZN) in selected tissues of rats after an oral administration in various combinations were analyzed. Male rats were orally dosed with diazinon (40 mg.L-1), diazinon (40 mg.L-1) +selenium (5 mg.L-1), diazinon (40 mg.L-1) +cadmium (30 mg.L-1), and diazinon (40 mg.L-1) +selenium (5 mg.L-1) +cadmium (30 mg.L-1) in drinking water. After 90 days of per oral administration of compounds, the samples of liver, kidney, muscle tissue (m. quadriceps femoris), and adipose tissue were collected. The content of DZN was analyzed using Gas Chromatography - Mass Spectrometry (GC-MS), Cd was analyzed using an Electrothermal Atomic Absorption Spectrometry (ETAAS) and Se using a Hydride Generation Atomic Absorption Spectrometry (HG-AAS) methods. Cadmium significantly increased in liver and kidney after DZN +Cd and DZN +Se +Cd administration. Se significantly increased in liver of DZN +Se, DZN +Se +Cd and DZN +Cd exposed rats, in kidney of DZN +Se and DZN +Se +Cd and DZN +Cd, and in muscle of DZN +Se +Cd group. Highest DZN content was found in the adipose tissue in DZN, DZN +Cd and DZN +Se +Cd but not in combined exposure with Se. Anyway, the differences between the control and experimental groups were not significant. The results indicate that cadmium and selenium accumulate mainly in liver, kidney and selenium also in muscle after p.o. administration but diazinon concentrations increases were not signifcant. The co-administration of diazinon, Se and Cd affects the content of these compounds in the organism and the accumulation rate depends on the combination of administered compounds. Diazinon and cadmium could contribute to the selenium redistribution in the organism after the peroral intake.

Effects of thirty elements on bone metabolism

The human skeleton, made of 206 bones, plays vital roles including supporting the body, protecting organs, enabling movement, and storing minerals. Bones are made of organic structures, intimately connected with an inorganic matrix produced by bone cells. Many elements are ubiquitous in our environment, and many impact bone metabolism. Most elements have antagonistic actions depending on concentration. Indeed, some elements are essential, others are deleterious, and many can be both. Several pathways mediate effects of element deficiencies or excesses on bone metabolism. This paper aims to identify all elements that impact bone health and explore the mechanisms by which they act. To date, this is the first time that the effects of thirty minerals on bone metabolism have been summarized.

Simultaneous subchronic exposure to selenium and diazinon as possible risk factor for osteoporosis in adult male rats

BACKGROUND

Osteoporosis and its main health outcome, fragility fractures, are large and escalating health problems. Skeletal damage may be the critical result of low-level prolonged exposure to several xenobiotics in the general population, but the mechanisms of their adverse effects are not clearly understood. The current study was aimed to investigate the possible ability of simultaneous subchronic peroral administration of selenium (Se) and diazinon (DZN) to induce changes in bone of adult male rats.In our study, twenty 1-month-old male Wistar rats were randomly divided into two experimental groups. In the first group, young males were exposed to 5 mg Na2SeO3/L and 40 mg of DZN/L in drinking water, for 90 days. Ten 1-month-old males without Se and DZN intoxication served as a control group. At the end of the experiment, macroscopic and microscopic structures of the femurs were analysed using analytical scales, sliding instrument, and polarized light microscopy.

RESULTS

The body weight, femoral length and cortical bone thickness were significantly decreased in rats simultaneously exposed to Se and DZN (P < 0.05). These rats also displayed different microstructure in the middle part of the compact bone where vascular canals expanded into central area of substantia compacta. The canals occurred only near endosteal surfaces in rats from the control group. Additionally, a smaller number of primary and secondary osteons, as well as a few resorption lacunae were observed near endosteal surfaces in rats simultaneously administered to Se and DZN. The resorption lacunae as typical structures of bone resorption manifestation are connected with an early stage of osteoporosis. Histomorphometric analysis revealed that area, perimeter, maximum and minimum diameters of primary osteons' vascular canals were significantly increased (P < 0.05) in the Se-DZN-exposed rats. On the other hand, all measured variables of Haversian canals and secondary osteons were considerable reduced (P < 0.05) in these rats.

CONCLUSIONS

Simultaneous subchronic peroral exposure to Se and DZN induces changes in macroscopic and microscopic structures of the femurs in adult male rats, and also it can be considered as possible risk factor for osteoporosis. The current study contributes to the knowledge on damaging impact of several xenobiotics on the bone.