A Comprehensive Histological Assessment of Osteoarthritis Lesions in Mice

Abstract

Objective:Accurate histological assessment of osteoarthritis (OA) is critical in studies evaluating the effects of interventions on disease severity. The purpose of the present study was to develop a histological grading scheme that comprehensively and quantitatively assesses changes in multiple tissues that are associated with OA of the stifle joint in mice.Design:Two representative midcoronal sections from 158 stifle joints, including naturally occurring and surgically induced OA, were stained with H&E and Safranin-O stains. All slides were evaluated to characterize the changes present. A grading scheme that includes both measurements and semiquantitative scores was developed, and principal components analysis (PCA) was applied to the resulting data from the medial tibial plateaus. A subset of 30 tibial plateaus representing a wide range of severity was then evaluated by 4 observers. Reliability of the results was evaluated using intraclass correlation coefficients (ICCs) and area under the receiver operating characteristic (ROC) curve.Results:Five factors were retained by PCA, accounting for 74% of the total variance. Interobserver and intraobserver reproducibilities for evaluations of articular cartilage and subchondral bone were acceptable. The articular cartilage integrity and chondrocyte viability factor scores were able to distinguish severe OA from normal, minimal, mild, and moderate disease.Conclusion:This newly developed grading scheme and resulting factors characterize a range of joint changes in mouse stifle joints that are associated with OA. Overall, the newly developed scheme is reliable and reproducible, characterizes changes in multiple tissues, and provides comprehensive information regarding a specific site in the stifle joint.

Expression of p16INK4a is a biomarker of chondrocyte aging but does not cause osteoarthritis

“…Briefly, the four quadrants of the load‐bearing region (medial and lateral sides of the femoral condyle and tibial plateau) were summed after grading on a 0–12 scale, with 12 representing complete loss of staining or tissue over more than 2/3 of the surface. An articular cartilage structure score was also generated as previously described (McNulty et al., 2011), which showed similar results to the Safranin‐O staining score but with less sensitivity to subtle changes in OA progression (data not shown). Slides stained with hematoxylin and eosin were used to assess osteophyte score, with each quadrant graded on a 0–3 scale for osteophyte size as previously described (Rowe et al., 2017).…”

“…Littermate cohorts of Acan tm1(cre/ERT2)Crm p16 INK4a+/+ and Acan tm1(cre/ERT2)Crm p16 L/L male mice were treated with tamoxifen at 4 and 12 months of age to induce p16 INK4a loss. The development of OA was evaluated in mice sacrificed at 18 months of age using established histological scoring systems based on the loss of Safranin‐O staining and osteophyte formation in the load‐bearing cartilage of the femoral condyle and tibial plateau (McNulty et al., 2011). Spontaneous age‐related OA occurs with variable progression in male C57BL/6 mice, and our histological results underscored this variability by demonstrating mild, moderate, and severe OA at 18 months of age (Figure 4a).…”

“…Joints were embedded in paraffin and coronal sections of 4–5 μm were taken from the mid‐coronal plane for histological assessment. Slides stained with Safranin‐O (proteoglycans)/Fast Green (collagen)/Hematoxylin (nuclei) were used to analyze a Safranin‐O score as previously described (McNulty et al., 2011). Briefly, the four quadrants of the load‐bearing region (medial and lateral sides of the femoral condyle and tibial plateau) were summed after grading on a 0–12 scale, with 12 representing complete loss of staining or tissue over more than 2/3 of the surface.…”

A mouse model for chronic pain-induced increase in ethanol consumption

“…The evaluation included the Articular Cartilage Structure (ACS) score (0–12), synovial hyperplasia severity score in the medial compartment (0–3; 0 = 1 cell layer in synovium, 1 = 2–3 cell layers, 2 = 4–5 cell layers, and 3 = 5 or more cell layers), and osteophyte score for the medial tibial compartment (0–3) [13]. An adjacent slide (~ 70 um apart) was stained with safranin O/fast green and the Safranin-O (Saf-O) staining score (0–12) [15] for the medial tibial compartment was obtained.…”

Musculoskeletal system

“…Coronal sections through the stifle joint where the patella is embedded face down may be useful for a more detailed assessment and scoring of damage to cartilage in the stifle joint (van Valburg et al 1996). Scoring systems for damage to the articular surface have been developed for mice (Glasson et al 2010;McNulty et al 2011) adapted from the Mankin system widely used to assess human joint tissue (Mankin et al 1971).…”