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Changes in the mechanical properties of femoral cartilage tissue in advanced osteoarthritis

Dragan Szymon Ł., Kuropka Piotr, Kulej Mirosław, Gabryś Piotr, Nikodem Anna

Acta of Bioengineering and Biomechanics

2020

Vol. 22, no. 1

143--152

The main goal of this article was the analysis of the changes of mechanical properties, thickness and histology of the cartilage in different regions of the femur head in advanced stage of the osteoarthritis. Methods: The study material consisted of cylindrical specimens (9.7 mm) prepared form proximal epiphysis of the human femur bone after hip arthroplasty. The thickness was determined from the reconstruction of the specimen from microtomography (SkyScan 1172, Bruker®) images. Mechanical properties of the cartilage tissue were identified in static indentation test conducted the use of MTS® Synergie 100 testing machine. Histological study enabled us to determine cartilage total thickness as well as location and orientation of the collagen fibers. Results: Depending on the region of the head, the cartilage tissue thickness was in the range (0.74–2.23 mm). The lowest thickness values were obtained for the R5 region and the lowest for R4. Samples from R1–R4 regions differ by 24%. Measurements of cartilage tissue indentation, determined with the help of Hayes’ formula, showed that the values of mechanical parameters in regions R1, R2, R3 and R5 have similar values (the difference between them is about 5.5%). Region R4, which had the smallest thickness, also had the lowest values of mechanical parameters. Conclusions: Using κ coefficients, proposed by Hayes, enabled us to obtain similar values of mechanical parameters in the regions R1, R2, R3 and R5, despite differences in cartilage tissue thickness. The R4 region, which had the weakest mechanical parameters, was characterized by the strongest reduction of the articular cartilage tissue, which was accompanied by an unformed mass of cartilage residue originating from the abraded surface and bursa fluid.

Thermographic evaluation of experimental pleurisy induced by carrageenan and modified by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Kuropka Piotr, Dobrzyński Maciej, Tarnowska Małgorzata, Dymarek Robert, Leśków Anna, Wiglusz Rafał J.

Acta of Bioengineering and Biomechanics

2019

Vol. 21, no. 3

23--29

The use of a thermal imaging camera may improve the detection of changes during inflammation process propagation in animals and humans that could be caused by numerous factors like 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Methods: Rats were randomised and divided into two groups, C group, in which experimental pleural inflammatory reaction was evoked and TCDD group, in which a single dose was applied 21 days before administration of 1% carrageenan solution. Infrared thermograms were taken with a microbolometer thermal imaging camera MobIR M8. The surface temperature distribution was measured in three randomly selected animals. Results: In the analysis of correlation we found negative results between both groups. In the C group, the pleurisy was developed and allowed to develop freely. It can be observed that both the average maximum temperature and the average minimum temperature were the highest after 48 hours after injection of the 1% carrageenan in solution. In TCDD group, lowered temperature in all days of experiments was noted. However, the increase of temperature after carrageenan injection was similar. The main changes observed in the lungs were oedema, hyperemia with clot formation and changes in lung structure. Several proliferative changes in the lungs were noted. Moreover, increased number of goblet cells as well and increased release of the surfactant was observed. The activation of fibroblasts and synthesis of collagen fibers was noted. Conclusions: The TCDD administration results in the reduction of superficial temperature, which is easily detectable by thermal imaging camera that can be effectively used in monitoring the course of inflammation.