Deformation patterns of cracked articular cartilage under compression

Abstract

difficulty in transfecting siRNAs in vivo. Recently, chemically modulated siRNAs which do not require transfection agents or other additional techniques such as electroporation in transfecting into cells have been developed. These siRNAs can be applied simply to cells with low cellular toxicity, and is likely to be suitable for in vivo use. Previous studies have demonstrated that the effects of intra-articular injection of ADAMTS5 or MMP13 siRNA into the knee on the delay and attenuation of articular cartilage degeneration. However, the effect of the combined siRNA injection of these two proteases is not clear. Therefore, purpose of this sturdy is to examine the effect of administration of chemically modulated MMP13 siRNA alone or in combination with ADAMTS5 siRNA in a mice OA model. Methods: OA pathology was surgically induced to C57BL/6 mice by destabilization of the medial meniscus (DMM) method, by transecting the medial meniscotibial ligament under general anesthesia. Three different siRNA injections against the DMM model were evaluated. MMP13 siRNA group was injected chemically modulated MMP13 siRNA one week after DMM surgery. Combined siRNA group was injected ADAMTS5 siRNA three days after the surgery and MMP13 siRNA four days later. Control siRNA group was injected non targeting siRNA which does not target to any gene. Histological assessment of articular cartilage at 8 weeks post DMM surgery was conducted to assess the effect of siRNA injections in osteoarthritis progression, according to the OARSI recommendation for OA knee scoring in mice. Results: Fibrillation and loss of Safranin O staining of the cartilage surface were observed in control siRNA group. Improvement was observed in the histological score in both treated group compared to the control siRNA injected group. Especially in combined siRNA group, the score was lower than MMP13 siRNA group. Conclusions: Combined treatment with MMP13 siRNA and ADAMTS5 siRNA intra-articular injection can be expected to inhibit cartilage degradation at the early phase of OA development compared to treatment MMP13 siRNA alone.

Stress behaviors of distal femoral cartilage defect and repair

“…Cartilage degeneration caused by unnormal contact stress could eventually cause osteoarthritis [20,21] . In this study, stress distributions of defective cartilage and arti cial repaired cartilage in the femoral condyle surfaces were analyzed to reveal mechanical mechanism of cartilage defect and rehabilitation.…”