Abstract: Abstract: The influence of pregnancy on bone tissue metabolism is not completely understood. Caffeine also has a potentially negative influence on bones. The aim of this study was the evaluation of changes in the bones of pregnant rats under the influence of caffeine. The experiment was carried out on Wistar rats. The evaluation of rats' bone tissue quality was performed based on bone density measurements and resistance examinations. It analyzed the impact of caffeine on the degree of bone tissue mineralization and the composition of the bones. The mean value of pelvises 'wet' and 'dry' densities in a group of pregnant rats with caffeine intake was lower compared to the control group. The deformation in maximal load point of the femur shaft in the experimental group was significantly higher than in the control group. In the experimental group, the percentage of water in the bones was significantly higher, while the content of inorganic phase was significantly lower compared to the control group. The changes of biomechanical parameters in the group of pregnant rats with caffeine intake indicate its negative influence on the bone. Our results show higher plasticization of the bone shafts of the animals under the influence of caffeine. Higher deformation of bone shafts may have an effect on the statics of the skeleton. The administration of caffeine significantly affected the quantitative composition of the bone.

Bisphosphonates (BPs) are well-known substances with very efficient antiresorptive properties. Their beneficial actions are useful not only in achieving better bone mineral density but also in improving bone microarchitecture, strength and, consequently, its quality. Surgical cement, being a polymer composite, is required to be highly biocompatible and biotolerant. The goal of the presented study was to assess whether the enrichment of cement with pamidronate has changed its biomechanical properties. We compared the biomechanical parameters of clean bone cement and BP-enriched bone cement, which were both used formerly in our rat models. Biomechanical properties of BP-enriched bone cement are defined by two basic terms: stress and strain, which are caused by the influence of external force. In the investigatory process of the bone’s biomechanical parameters, the compressive test and the three-point flexural tests were used. During the three-point flexural investigation, the sample was supported at both ends and loaded in the middle, resulting in a flexure. After a specific range of flexure, the sample was fractured. In obtained results, there were no significant differences in the values of the stress determined at the point of maximal load and the energy stored in the samples for proportional stress–strain limit (elastic region). There were also no significant differences in the density of the samples. The study shows that the enrichment of bisphosphonates causes yielding of the bone cement material. In the presented data, we conclude that use of pamidronate implanted in bone cement did not have a detrimental effect on its biomechanical properties. Therefore, the obtained results encouraged us to perform further in vivo experiments which assess the biomechanical properties of bones implanted with BP-enriched bone cement.

Abstract:Caffeine is a methylxanthine which permeates the placenta. In studies on animals, it has been shown to produce teratogenic and embryotoxic effects in large doses. The objective of this study was to assess the influence of caffeine on the development of bone tissue, with particular reference to elemental bone composition using an X-ray microprobe. The research was conducted on rats. The fertilized females were randomly divided into an experimental and a control group. The experimental group was given caffeine orally in 30 mg/day doses from the 8 th to the 21 st day of pregnancy, while the control group was given water. The fetuses were used to assess the growth and mineralization of the skeleton. On the basis of double dyeing, a qualitative analysis of the bone morphology and mineralization was conducted. For calcium and potassium analysis, an X-ray microprobe was used. In 67 fetuses from the experimental group, changes in skeleton staining with the alcian-alizarin method were noticed. The frequency of the development of variants in the experimental group was statistically higher. In the experimental group, a significant decrease in the calcium level, as well as an increase in the potassium level, was observed. The X-ray microprobe's undoubted advantage is that is offers a quick qualitative and quantitative analysis of the elemental composition of the examined samples. Employing this new technique may furnish us with new capabilities when investigating the essence of the pathology process.

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