A Stereological Method for the Quantitative Evaluation of Cartilage Repair Tissue

Abstract

ObjectiveTo implement stereological principles to develop an easy applicable algorithm for unbiased and quantitative evaluation of cartilage repair.DesignDesign-unbiased sampling was performed by systematically sectioning the defect perpendicular to the joint surface in parallel planes providing 7 to 10 hematoxylin–eosin stained histological sections. Counting windows were systematically selected and converted into image files (40-50 per defect). The quantification was performed by two-step point counting: (1) calculation of defect volume and (2) quantitative analysis of tissue composition. Step 2 was performed by assigning each point to one of the following categories based on validated and easy distinguishable morphological characteristics: (1) hyaline cartilage (rounded cells in lacunae in hyaline matrix), (2) fibrocartilage (rounded cells in lacunae in fibrous matrix), (3) fibrous tissue (elongated cells in fibrous tissue), (4) bone, (5) scaffold material, and (6) others. The ability to discriminate between the tissue types was determined using conventional or polarized light microscopy, and the interobserver variability was evaluated.ResultsWe describe the application of the stereological method. In the example, we assessed the defect repair tissue volume to be 4.4 mm3 (CE = 0.01). The tissue fractions were subsequently evaluated. Polarized light illumination of the slides improved discrimination between hyaline cartilage and fibrocartilage and increased the interobserver agreement compared with conventional transmitted light.ConclusionWe have applied a design-unbiased method for quantitative evaluation of cartilage repair, and we propose this algorithm as a natural supplement to existing descriptive semiquantitative scoring systems. We also propose that polarized light is effective for discrimination between hyaline cartilage and fibrocartilage.

Collagen Type IV and Laminin Expressions during Cartilage Repair and in Late Clinically Failed Repair Tissues from Human Subjects

“…Stereological analysis of human tissue biopsies as those in the present study is not possible without the risk of selection bias or confounding. 17 Additional studies applying quantitative protein analysis during cartilage repair by means of targeted proteomics may provide additional quantitative information of these proteins and their roles in cartilage repair.…”

“…These were correlated with the tissue morphology based on previously published criteria (hyaline cartilage, fibrocartilage, fibrous tissue, or bone). 17 …”

Biocompatible chitosan–collagen–hydroxyapatite nanofibers coated with platelet-rich plasma for regenerative engineering of the rotator cuff of the shoulder

“…Nanober implants were tried in ovine meniscus repair models, where they improved cell recruitment, rebuilding, vascularization and the renovation of tissue integration in comparison with the addition of PRP or wrapping of the meniscus with a COLL layer. 30,31 In conclusion, the prepared nanober inserts improved marrow-animated ligament repair and initiated bone remodeling in the animal model. We theorized that the majority of the above techniques would likewise be benecial for RCF, and we subsequently demonstrated in a rat model that the prepared nanober implants improve trans-osseous RCF via favoring ligament connection by expanded bone tissue remodeling.…”

Time-dependent regulation of morphological changes and cartilage differentiation markers in the mouse pubic symphysis during pregnancy and postpartum recovery

“…Metachromatic hyaline cartilage tissue volumes in NP and at 10dpp were morphometrically estimated by point counting according to Foldager et al [ 61 ], and the differences between numerical data obtained in both groups were analysed by performing a Mann-Whitney nonparametric test; differences with p<0.05 were considered significant, and the analysis was performed using GraphPad Prism 5.0 (GraphPad Software, Inc., California, USA). Differences in metachromatic hyaline cartilage tissue volumes between NP and 10dpp PS were obtained using the Mann-Whitney nonparametric test and plotted on a graph, and the mean SEM values are represented using bars.…”