Assessment of bone tissue cytoarchitectonics by 2D 1H NMR relaxometry maps.

Bone is a complex tissue that fulfills the role of a resistance structure. This quality is most commonly assessed by bone densitometry, but bone strength may not only be related to bone mineral density but also to the preservation of bone cytoarchitectonics. The study included two groups of rats, ovariectomized and non-ovariectomized. Each group was divided into three batches: control, simvastatin-treated, and fenofibrate-treated. In the ovariectomized group, hypolipidemic treatment was instituted at 12 weeks post ovariectomy. One rat from each of the 6 batches was sacrificed 8 weeks after the start of treatment in the group. The experimental study was performed using a Bruker Minispec mq 20 spectrometer operating at a frequency of 20 MHz, subsequently also performed by 1H T2-T2 molecular exchange maps. The results were represented by T2-T2 molecular exchange maps that showed, comparatively, both pore size and their interconnectivity at the level of the femoral epiphysis, being able to evaluate both the effect of estrogen on bone tissue biology and the effect of the lipid-lowering medication, simvastatin, and fenofibrate, in both the presence and absence of estrogen. T2-T2 molecular exchange maps showed that the absence of estrogen results in an increase in bone tissue pore size and interconnectivity. In the presence of estrogen, lipid-lowering medication, both simvastatin and fenofibrate alter bone tissue cytoarchitectonics by reducing pore interconnectivity. In the absence of estrogen, fenofibrate improves bone tissue cytoarchitectonics, the T2-T2 molecular exchange map being similar to that of non-osteoporotic bone tissue.

Evaluation of the Influence of Hypolipidemic Medication on Albino Wistar Rats' Bone Tissue by NMR Diffusiometry.

Introduction: The ongoing concern of the medical profession regarding chronic medication is related to increasing patient adherence and compliance to treatment and reducing medication side effects. In this respect, drugs represented by fixed-dose combinations of active substances within the same tablet have emerged. Such a principle can be extrapolated by following the potential beneficial effects that a chronic medication can have on chronic pathologies affecting different systems. Materials and Methods: The study included 48 female Albino Wistar rats, aged 16-18 months, which were divided into two groups: ovariectomized and non-ovariectomized rats. One batch of 12 non-ovariectomized rats received no treatment, becoming a control batch (NOVX-M). The ovariectomized (OVX) group was divided into 3 batches of 12 rats each: no treatment, control (OVX-M), fenofibrate-treated (OVX-F) and statin-treated (OVX-S) rats. At 12 weeks after ovariectomy, a femoral fracture occurred in the right hind limb of all animals included in the experiment To reveal the changes, at intervals of 2, 4, 6 and 8 weeks post-fracture, the proximal part of the femur was evaluated by NMR diffusiometry, which allows random motion of proton molecules expressed by self-diffusion coefficients, D, thus allowing analysis of the size and complexity of microscopic order cavities within biological structures, such as pores inside bones. Results: The effects of hypolipidemic medication in the absence of estrogen were evidenced, proving the beneficial effect that fenofibrate can have in preserving healthy tissue exposed to osteoporotic risk during the menopausal period. The effects of lipid-lowering medication are also influenced by the duration of administration. Conclusions: Osteoporosis and heart disease are two chronic pathologies that affect mainly female population in the second half of life, and proving the dual therapeutic potential of lipid-lowering medication may also have positive effects by increasing adherence and compliance to treatment.

Callus formation in albino Wistar rats after femur fracture assessed by visible spectroscopy.

Classical histological methods such as hematoxylin-eosin staining, have been, and in some areas still are, an important benchmark for the evaluation of biological tissues. However, the current method of assessment is primarily a qualitative assessment of the tissue under investigation. The aim of this paper is to contribute to the improvement of classical histological methods, by applying physical techniques that allow objective, quantitative data to be added to qualitative assessments, especially in areas where conflicting results are available. To this end, the effect of hypolipidemic medication on the callus formation process of normal bone and pathological osteoporotic bone was investigated. The study allowed us to associate UV-VIS spectroscopy wave number with specific hematoxylin-eosin staining of different types of bone tissue structures, the evolving structures in the callus formation process. This association allowed the quantitative assessment of the callusing process in ovariectomized (associated with pathological, osteoporotic bone) and non-ovariectomized (associated with normal bone) rats, with three groups - the control group, simvastatin-treated group, and fenofibrate-treated group. The study showed that in the non-ovariectomized groups both treatments delayed callus formation. In the ovariectomized groups, simvastatin delayed and fenofibrate promoted callus formation.

Ovariectomized rats' femur treated with fibrates and statins. Assessment of pore-size distribution by ¹H-NMR relaxometry.

The effects of two wonder drugs, simvastatins and fenofibrates on the proximal part of the femoris of a series of ovariectomized and non-ovariectomized Wistar albino rats was estimated qualitatively and semi-quantitatively by the modern method of 1D 1H-NMR T2-distribution. The 72 rats subjected to this study were divided in six groups and were sacrificed at two, four, six and eight weeks after ovariectomy and the proximal part of femoris was harvested. The CPMG (Carr-Purcell-Meiboom-Gill) echoes train curves were measured for the bones fully saturated with water during two months after two months of natural drying. These decays were analyzed by Laplace inversion and an average of normalized T2-distributions was considered for all rat's groups. The 1D averaged T2-distributions present four peaks, which were associated with protons in four major environments, from which the free water protons are used as spy molecules to explore the boundaries of cavities. In the approximation of spherical pores, the averaged T2-distributions were transformed in distributions of pores diameters. These were found in the range from 2 µm up to 2 mm. The relative amplitudes, widths and position of deconvoluted distributions of small, medium and large cavities are used for a qualitatively analysis of the effect of our lipid-lowering drugs. For a semi-quantitatively analysis, we chose the diameter d of proximal part of femoris' trabecular cavities. We show that the positive or negative effects of treatments with simvastatins and fenofibrates are strongly dependent on the duration of treatment. Moreover, the treatment of healthy bone is generally counter-indicated.