Early Response of Mouse Joint Tissue to Noninvasive Knee Injury Suggests Treatment Targets

Abstract

Objective Joint trauma can lead to a spectrum of acute lesions, including cartilage degradation, ligament or meniscus tears, and synovitis, all potentially associated with osteoarthritis. The goal of this study was to generate and validate a murine model of knee joint trauma following non-invasive controlled injurious compression in vivo and to investigate early molecular events. Methods The right knees of 8-week old mice were placed in a hyperflexed position and subjected to compressive joint loading at one of three peak forces (3, 6, 9 N) for 60 cycles in a single loading period and harvested at 5, 9 and 14 days post loading (n=3–5 mice for each time point and for each loading). The left knees were not loaded and served as the contralateral controls. Histological, immunohistochemical and ELISA analyses were performed to evaluate acute pathologic features in chondrocyte viability, cartilage matrix metabolism, synovial reaction, and serum COMP levels. Results Acute joint pathology was associated with increased injurious loads. All loading regimens induced chondrocyte apoptosis, cartilage matrix degradation, disruption of cartilage collagen fibril arrangement, and increased levels of serum COMP. We also observed that 6N loading induced mild synovitis by day 5 whereas at 9 N, with tearing of the anterior cruciate ligament, severe posttraumatic synovitis and ectopic cartilage formation were observed. Conclusion We have established and analyzed some early events in a murine model of knee joint trauma with different degrees of over-loading in vivo. These results suggest that immediate therapies particularly targeted to apoptosis and synovial cell proliferation could affect the acute posttraumatic reaction to potentially limit chronic consequences and osteoarthritis.

Suppression of NF-κB activity via nanoparticle-based siRNA delivery alters early cartilage responses to injury

“…Experiments were performed on 8-wk-old male C57BL/6J mice (The Jackson Laboratory) using a materials testing machine (Instron ElectroPuls E1000) as previously described (5). Briefly, under anesthesia, the right tibiae were positioned with the knee downward in deep flexion between custom-made cups and subjected to axial compressive loads with a peak force of 6 Newtons (N) with a 0.5 N preload force to maintain the limb in position between loading cycles.…”

“…Formalin-fixed knee joints were decalcified and embedded in paraffin for sectioning. Serial sagittal sections (5 μm in thickness) from individual knees were cut through the entire lateral femoral condyle as described previously (5). Selected sections were stained with Safranin O-fast green (to evaluate articular cartilage proteoglycan content), according to standard protocols.…”

“…To gain further insights into these early events, we established a noninvasive model to induce cartilage injury by applying controlled compressive loads to mouse knee joint (5). This model allows the examination of molecular and structural events at specific time points postinjury.…”

Aging diminishes lamellar and woven bone formation induced by tibial compression in adult C57BL/6

“…After each loading session, mice received buprenorphine (0.1 mg/kg i.m.) to mitigate any pain associated with knee joint injury [31], and were returned to their cages where they were observed to resume unrestricted activity. The left tibia served as a non-loaded, contralateral control.…”

In vivo cartilage strain increases following medial meniscal tear and correlates with synovial fluid matrix metalloproteinase activity

“…A variety of biomarkers of cartilage metabolism in the synovial fluid have been associated with the development of osteoarthritis, including matrix metalloproteinases (MMPs) (Baragi et al, 2009; Janusz et al, 2002; Pozgan et al, 2010), sulfated glycosaminoglycans (sGAGs) (Lindhorst et al, 2000; Lohmander et al, 1999), cartilage oligomeric matrix protein (COMP) (Carlson et al, 2002; Wu et al, 2014), prostaglandin E 2 (PGE2) (Nishimura et al, 2002), and C2C (Fraser et al, 2003), which is a type II collagen neoepitope released upon collagenase cleavage. However, the relationship between catabolic biomarkers in the synovial fluid and cartilage strains following meniscal injury has yet to be studied.…”