Nanomechanical Properties of Articular Cartilage Due to the PRP Injection in Experimental Osteoarthritis in Rabbits

Abstract

The purpose of this study was twofold. Firstly, we proposed a measurement protocol for the atomic force microscopy (AFM) method to determine the nanomechanical properties of articular cartilage in experimental osteoarthritis in rabbits. Then, we verified if mechanical properties can be evaluated with AFM shortly after platelet-rich plasma (PRP) injection. We hypothesized that the modulus determined by AFM indentation experiments could be utilized as a progressive disease marker during the treatment of osteoarthritis. The rabbits were equally divided into three groups of six: control (group 1); injections of saline (0.5 mL) and 10% surgical talc (Talcum Pharmaceutical®, Minsk, Belarus) were delivered into the right knee under the patella (group 2 and 3); and PRP was injected into the right knee (group 3). In group 2, the arithmetic average of absolute values (Ra) change was a 25% increase; the maximum peak height (Rp) increased by over 102%, while the mean spacing between local peaks (S) increased by 28% (p < 0.05). In group 3, Ra increased by 14% and Rp increased by 32%, while S decreased by 75% (p < 0.05). The Young’s modulus of the surface layers decreased by 18% as a result of induced model of osteoarthritis (IMO) (p < 0.05), and it increased by 9% (p < 0.05) as a result of PRP therapy, which means that the mechanical properties of cartilage were partially recovered. This research demonstrates that Young’s modulus utilized on a nanometer scale has potential to be a progressive disease marker during the treatment of osteoarthritis.

Atomic Force Microscopy Micro-Indentation Methods for Determining the Elastic Modulus of Murine Articular Cartilage

“…Aside from this, there was little difference in the results seen between PDMS and articular cartilage samples; ramp rate and size did not change the results on either substrate. With these parameters, the matrix stiffness of the middle zone of murine articular cartilage was approximately 2 MPa, which is similar to some of the values obtained from the literature [ 15 , 24 , 25 , 26 , 27 , 48 ]. These experiments, initially investigated on PDMS gel and then confirmed on articular cartilage, established experimental parameters to be used for consistent AFM characterization of the extracellular matrix in the middle zone of articular cartilage.…”

“…Including this baseline allows future examination of sex differences in post-traumatic osteoarthritis. Although comparing empirical values across studies is difficult, the elastic moduli reported here are similar to the values found in the literature for small mammalian articular cartilage stiffness under similar conditions (probes on the scale of 1–10 µm), which generally varies between 0.5 and 3 MPa [ 15 , 24 , 25 , 26 , 43 , 48 ]. Specifically, studies on murine samples with similar parameter choices obtained stiffnesses around 1–2 MPa [ 26 , 27 ].…”

A Bioinspired Hydrogel-Elastomer Hybrid Surface for Enhanced Mechanical Properties and Lubrication

“…The Young’s modulus of the hybrid surface was 100 times lower than substrates but 10–100 times higher than the pure PAAm hydrogel, , which demonstrated that the coating was a hybrid substance of the elastomer and the hydrogel. Interestingly, the surface Young’s modulus of hybrid surfaces matched closely to the superficial zone of the articular cartilage as reported (20–640 kPa). ,− Also, it was reasonable to presume that the modulus of the sample with the hybrid surface was heterogeneous from the outermost to the bottom side like the articular cartilage. A similar compressive modulus with the articular cartilage may ensure that the samples achieve a high load bearing successfully.…”

Platelet-rich plasma injections induce disease-modifying effects in the treatment of osteoarthritis in animal models

“…These indings were conirmed by phase-contrast computed tomography (CT), revealing greater cartilage volume and surface in mice treated with PRP [37]. Histologically, better cellularity was seen following PRP administration, which prevented chondrocyte apoptosis and increased their viability with increased proliferative rate, resulting in higher chondrocyte numbers [6,9,10,18,35,68]. Chondrocytes also showed better ultrastructural characteristics with a relatively intact cell membrane, abundant cellular organelles, roughly normal nuclear morphology, and relatively uniform cytoplasmic staining [66].…”