Télécharger la vidéo (16.07 MB - wmv) (16.07 MB)Researchers at INSERM have decided to enlist the DISCO beamline’s UV radiation to study the changes to our skeletal system caused by osteoporosis and the effectiveness of treatments...
OSTEOPOROSIS
With age, our bones inevitably become more porous and fragile. This disease, which is particularly frequent in women after menopause, is called osteoporosis. What changes does our skeletal system undergo at that time? Are the treatments prescribed for osteoporosis really effective in restoring bone tissue to its original structure? To answer these questions, several researchers from the French national institute of health and medical research, Inserm, decided to draw on the remarkable properties of synchrotron radiation, and in particular the DISCO beamline’s ultraviolet radiation.
Gaël Rochefort, Doctor in Life Sciences and Health (Inserm)
Bone is composed of two main parts: a cellular part – the small white dots here, primarily osteocytes –, and a mineral part: the bone matrix.
We are looking at this osteocyte and its immediate vicinity in synchrotron spectroscopy, as well as a much more distant part constituted exclusively of mineral and organic matrix.
Osteocytes produce the matrix which gives bones their rigidity. It was therefore important for the researchers to examine the transformations that occur within these two structures, by means of ultraviolet radiation.
This animal study is being conducted on rats in which an osteoporosis phenomenon was artificially induced. Fine strips of bone, barely 1 micron thick, are prepared and placed under the lens of the microscope.
Gaël Rochefort
There, you see the bone matrix, the mineralized part of bone tissue. And there’s the osteocyte in the centre, which is the most common cell in bone tissue. You can see small bits jutting out just about everywhere; these are dendrites, membrane extensions through which the cells send information to other cells. This is how cells communicate with each other.
Stéphane Pallu, Lecturer in biology (University of Orléans - Inserm)
It's rather similar to certain neuronal phenomena, except that here, it’s mineralized. The first publications that began to really bring out the role of this cell in bone remodelling only date from 2008. So this is something quite recent, and it’s a great opportunity to be able to work on the synchrotron and the DISCO beamline to discover its characteristics.
After demarcating the area to be analyzed, the ultraviolet beam excites the sample, point by point. Since each molecule reacts in a unique way to this excitation, it is possible to determine the constituents of bone tissue.
Stéphane Pallu
For instance on this spectrum, there are three peaks that stand out.
This peak corresponds to DNA, a nitrogenous base of DNA. It's quite interesting, because we will be able to study variations in these peaks under healthy and patho-physiological conditions.
Here, we have some amino acids, which are essential constituents of proteins. There too, we are likely to find fluctuations between healthy and patho-physiological conditions – for example, osteoporosis, chronic alcoholism and so on.
And you also have variations in another protein – collagen –, which is the major constituent of the organic part of bone.
Through these spectrums, scientists hope to obtain new information on the activity of bone cells and the structure of the matrix. Longer-term, the objective is to determine the most effective treatments for osteoporosis – which could really restore bone structure – and even help design the treatments of the future.