Enhanced In Vitro and In Vivo Efficacy of Alginate/Silk Protein/Hyaluronic Acid with Polypeptide Microsphere Delivery for Tissue Regeneration of Articular Cartilage

Alginate/Silk fibroin/hyaluronic acid (ALG/SF/HA) nanocomposites were synthesised using blending, inter-linking, and lyophilization methods. We investigated the physicochemical properties of the resulting nanocomposites, including their water retention, weight loss, porosity and cytocompatibility. The optimum ratios of the ALG/SF/HA scaffolding were 3:6.5:0.5. Nanocomposites with optimum ratios were then prepared by integrating pilose antler polypeptides (PAPS) to poly(lactic-co-glycolic acid) (PLGA) microspheres, and the performance was investigated. PAPS-ALG/SF/HA nanocomposites exhibited desirable adhesions and proliferations. Rabbit cartilage deficiencies was developed by the animal model. The cartilage repair effects deficiencies were detected and analyzed between PAPS-SF/ALG/ALG/SF/HA, and control activity classes. The deficiencies were virtually fully remedied after 13 weeks in the presence of PAPS-ALG/SF/HA class, suggesting that the PAPS-ALG/SF/HA nanocomposites had a positive effects on joint cartilage repair.

The technique of articular rabbit cartilage roughness measurement and analysis of the effect of PRP in knee osteoarthritis therapy using atomic force microscopy

Hyaline cartilage undergoes degenerative-dystrophic changes with subsequent involvement of the subchondral bone. The purpose of this study was developing a new AFM-based method to articular rabbit cartilage roughness measurement, followed by an investigation of whether platelet-rich plasma therapy of knee osteoarthritis has a positive impact on mechanical properties of rabbit cartilage. The rabbits were randomly divided into two groups: the control group (N=6) and the patients (N=12). Saline (0.5 ml) and 10% surgical talc solution were injected into the right knee of 12 rabbits to induce osteoarthritis. Six rabbits underwent PRP therapy, while the other six did not receive treatment. The mechanical properties and the submicron surface morphology rabbit hyaline cartilage were investigated using atomic force microscopy (AFM). In the group of specimens worn out by induced osteoarthritis, the maximum arithmetic average of absolute values (Ra) change was a 23% increase; the maximum peak height (Rp) increased by over 100%, while the mean spacing between local peaks (S) increased by 26%, compared to healthy rabbit cartilage (p<0.05). In the group of specimens worn out by induced osteoarthritis and cured with PRP therapy, Ra increased by 13%; Rp increased by 33%, while S decreased by 77%, compared to healthy rabbit cartilage (p<0.05). It was found that the mechanical properties of hyaline cartilage deteriorate under the influence of simulated osteoarthritis. The results of PRP treatment in rabbits may constitute a step forward to further relevant studies involving OA patients.

Calcium Phosphate Bioceramic Material Local Influence on the Bone Biomechanical Properties at Rabbits with Experimental Osteoporosis

Biomechanical characteristics of the rabbit cartilage component from the femur were investigated. The control osteoporosis had been activated by ovariectomy alongside the injections of methylprednisolone. During the experiment defects in the femur’s greater trochanter zone was created and afterwards filled with the fragments of a hydroxyapatite as well as tricalcium phosphate (HAP/TCP 70/30) or HAP/TCP 70/30 mixed with five percent strontium. Three months later animals were euthanazed, squared samples were cut out from the femur’s body and later tested on a bend. The results of the research revealed that the femurs become more stringent after filling off defects in the greater trochanter zone with HAP/TCP 70/30 or HAP/TCP 70/30 mixed with five percent strontium. The ultimate pain for the cartilage component in the control groups was less, than in the test group. The flexure modulus of flexibility of a cartilage component in the test group was statistically reliable less, than the value of the flexure modulus of flexibility of the cartilage component in the control groups. Therefore, local usage of calcium – phosphatic bioceramic component over the greater trochanter part increases biomechanical characteristics of the cartilage component in the femur of animals.