Veronika Kovacova

Acrylamide, a substituted unsaturated hydrocarbon, is often found in fried potatoes, flour, baby food, coffee, and olives. It is one of the most commonly consumed neurotoxins by humans. To date, its effect on bone structure has not been investigated in experimental animals. The aim of our manuscript was to analyze the impact of subacute exposure to acrylamide on the microscopic compact and trabecular bone tissue structures in laboratory mice. Adult male mice were divided into two groups. Animals from the experimental group (group E, n = 4) were treated perorally with two doses of acrylamide (1 mg/kg b.w.) during 24 hours. The group without administration of AA served as a control (group C, n = 4). Three hours after the second dose of AA (after 27 hours), mice were killed and their femurs were used for microscopic analysis. Our results demonstrate that subacute exposure to acrylamide causes an absence of the primary vascular radial bone tissue in pars posterior of the endosteal border. Mice from E group had more intact secondary osteons in pars medialis of the middle part of compact bone. Also, a few resorption lacunae were found in pars anterior of periosteal borders in these mice. Subacute exposure to AA significantly decreased the size of the primary osteon vascular canals (P<0.05) in compact bone tissue. In trabecular bone tissue, the values for bone volume, trabecular number, and bone surface were significantly increased in mice from the E group. In contrast, the value for trabecular separation was significantly decreased in these mice.

Background: Quercetin is one of the best known flavonoids being present in a variety of fruits and vegetables. It has cardioprotective, anticarcinogenic, antioxidant, anti-inflammatory and antiapoptotic properties. Some studies suggest that quercetin has protective effects on bone. However, its influence on qualitative and quantitative histological characteristics of compact bone is still unknown. In our study, 12 clinically healthy five-month-old female rabbits were divided into four groups of three animals each. Quercetin was applied intramuscularly in various concentrations; 10 µg/kg body weight (bw) in the E1 group, 100 µg/kg bw in the E2 group, and 1000 µg/kg bw in the E3 group for 90 days, 3 times per week. Three rabbits without exposure to quercetin served as a control (C) group. Differences in femoral bone microstructure among groups were evaluated. Results: Qualitative histological characteristics of compact bone differed between rabbits from the E1 and E2 groups. Primary vascular longitudinal bone tissue was not found in some areas near the endosteal surface due to increased endocortical bone resorption. In addition, periosteal border of rabbits from the E1 group was composed of a thicker layer of primary vascular longitudinal bone tissue than in the other groups. In all groups of rabbits administered quercetin, a lower density of secondary osteons was observed. Histomorphometrical evaluations showed significantly decreased sizes of the primary osteons’ vascular canals in individuals from the E1 and E2 groups. Secondary osteons were significantly smaller in rabbits from the E1, E2, E3 groups when compared to the C group. Cortical bone thickness was significantly increased in females from the E1 and E2 groups. Conclusions: The results indicate that quercetin has not only a positive dose–response on qualitative and quantitative histological characteristics of the compact bone of female rabbits as it would be expected.

Background: Patulin, a toxic mold metabolite, has been found as natural contaminant of processed fruits, most notably apples, apple juices and other apple-based products. A number of adverse health effects in humans and animals are associated with patulin intoxication. The current study was performed to analyse possible toxic effects of patulin on femoral bone microstructure in adult rabbits in detail. Fourteen clinically healthy four-month-old rabbits of both sexes (6 males and 8 females) were included in the study. Animals from the experimental groups (group E♂, n = 3; group E♀, n = 4) were injected intramuscularly with patulin at dose 10 μg/kg body weight two times a week for 28 days. The dose of patulin was estimated based on the maximum permitted level of patulin for apple products intended for infants and young children. Three males and four females without patulin administration served as controls (groups C♂ and C♀). Cortical bone thickness and qualitative and quantitative histological characteristics of compact bone tissue were investigated. Results: Intramuscular applications of patulin significantly increased the thickness of cortical bone in both sexes of rabbits. In patulin-exposed males, an absence of primary vascular longitudinal bone tissue near the endosteal border was observed, which could be associated with intensive bone remodeling. Femoral diaphyses of females displayed a lower number of secondary osteons in the middle part of the substantia compacta , and occurrence of the osteons near the periosteum. This could indicate alterations in bone turnover. Histomorphometrical evaluations showed significantly increased sizes of the primary osteons’ vascular canals ( P < 0.05) in males exposed to patulin possibly due to mycotoxin-induced increased levels of testosterone. Conclusions: This study demonstrates significant impact of intramuscular application of patulin on bone microstructure in adult rabbits. Moreover, we have found that the effects of patulin on qualitative and quantitative histological characteristics of compact bone are sex-dependent.