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

Abstract

Introduction. Bone is a complex tissue that fulfils 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. Material and methods. The study included two groups of rats, ovarectomized and non-ovarectomized. Each group was divided into three batches: control, simvastatin-treated and fenofibrate-treated. In the ovarectomized group, hypolipidemic treatment was instituted at 12 weeks post ovarectomy. 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. Results. The results were represented by T2-T2 molecular exchange maps that showed, comparatively, both pore size and their interconnectivity at the level of the posterior 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 both in the presence and absence of estrogen. Conclusion. T 2-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.