How to reduce the number of experiments on animals

Continuing the previous topic about implants and prosthetics , the same scientific group proposed an interesting technology for laboratory studies of the behavior of an orthopedic implant in conditions as close as possible to the human body. The study can be carried out in vitro - that is, without the participation of laboratory animals.

Endoprosthetics - replacing a damaged joint or bone with a high-tech prosthesis is a complex operation, using the most advanced metal, ceramic and polymeric materials.

Any material for an implant passes a series of checks, including the biocompatibility and behavior of the material under mechanical stress. Since the results of such studies in traditional laboratory conditions are very different from actual indicators of wear, in order to check the behavior of the implant in a living organism, it is implanted into the body of a laboratory animal. After some time, usually about a year, the implant is removed and the biocompatibility and aging of the material are evaluated.

Scientists from the Center for Composite Materials NITU "MISiS" together with colleagues from the Technical University of Dortmund developed a technology to predict the wear of the prosthesis material under mechanical load in an environment close to real. Especially synthesized fluid that mimics the plasma of human blood, and high-tech servo-hydraulic installation completely replaced the experimental living sample.

The research material was the biomimetic ultrahigh-molecular polyethylene developed by the scientists from the Center for Composite Materials, NUST “MISiS”.

“We provided material and suggested using synthetic plasma, and our colleagues from the Technical University of Dortmund developed fatigue testing technology and conducted an experiment on their equipment,” comments Fedor Senatov, Ph.D. - The material was subjected to two types of mechanical load, imitating the load of the femoral and tibial bones: cyclic and static. Thanks to this experiment, we proved that it is possible in vitro to predict the behavior of an orthopedic implant in the conditions of a human body, without resorting to animal testing. ”

“Our desire was to offer an alternative that would reduce the number of tests on animals, which, from the point of view of the assessment of fatigue properties, are ineffective and questionable from the point of view of ethics. Another aspect was the ability to propose a new method that would allow the implant material to be tested for durability in the laboratory. In the global practice, so far there are no standards for the study of the fatigue properties of implants in the biomimetic environment, which is associated with great risks of using new materials. We work in the development of tests that allow you to accurately predict the life of the material. Similar experiments have already been carried out by the group of Professor Walter (approx. - the head of the research team from the German side) for metal and ceramic implants. For polymers, this experiment is still unique, and has no world analogues, ”says Marina Knyazeva, a representative of the research group of the Technical University of Dortmund.

Another significant advantage of the research technology proposed by scientists is the saving of time. If it may take about a year to assess the chemical aging of an implant under living body conditions, then durability tests require dozens of years. In vitro, the process of chemical aging and wear can be significantly accelerated. If the indicators of material wear are unsatisfactory, this will become quickly known, and it will be possible to continue experiments with other samples.

However, it’s too early to talk about the complete rejection of the role of laboratory animals in testing materials for prosthetics.

“Our technology will make it possible to compare several materials at once, without testing any of them on animals. However, when the most optimal material from the list is found, it will need to be tested already in vivo - in living organisms. This is due, above all, to the need to check the biocompatibility of the material, as well as its orthopedic parameters - after all, patients can meet a variety of features of the musculoskeletal system, “- explains Fedor Senates.

Thus, scientists propose an integrated technology to study the behavior of an implant, where experiments on accelerated aging in vitro will predict the lifetime of a potential implant, and subsequent in vivo tests will show its biocompatibility.

The original article can be found in the Journal of the Mechanical Behavior of Biomedical Materials .