This work was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (NIH) under Award Number R01 AR059088, the Department of Defense (DoD) under Research Award Number W81XWH-12-1-0304, and the Mary and Paul Harrington Distinguished Professorship Endowment.

All animal procedures included in this protocol were approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Kansas Medical Center, in compliance with all federal and state laws and regulations.
1. Creation of knee OA in mice
<ol>
	<li>Create a mouse model of knee OA by surgical destabilization of the medial meniscus (DMM) as described by Glasson et al.18 in 22 wild-type BALB/c mice at 10-11 weeks of age. Perform sham ...

<ol>
	<li>Kotlarz, H., Gunnarsson, C. L., Fang, H., Rizzo, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insurer+and+out-of-pocket+costs+of+osteoarthritis+in+the+US:+evidence+from+national+survey+data.">Insurer and out-of-pocket costs of osteoarthritis in the US: evidence from national survey data.</a> Arthritis and Rheumatology. 60 (12), 3546-3553 (2009).</li><li>Buckwalter, J. A., Martin, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoarthritis.">Osteoarthritis.</a> Advanced Drug Delivery Reviews. 58 (2), 150-167 (2006).</li><li>Weinans, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology+of+peri-articular+bone+changes+in+osteoarthritis.">Pathophysiology of peri-articular bone changes in osteoarthritis.</a> Bone. 51 (2), 190-196 (2012).</li><li>Baker-LePain, J. C., Lane, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+bone+architecture+and+anatomy+in+osteoarthritis.">Role of bone architecture and anatomy in osteoarthritis.</a> Bone. 51 (2), 197-203 (2012).</li><li>Li, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subchondral+bone+in+osteoarthritis:+Insight+into+risk+factors+and+microstructural+changes.">Subchondral bone in osteoarthritis: Insight into risk factors and microstructural changes.</a> Arthritis Research and Therapy. 15 (6), 223 (2013).</li><li>Madry, H., van Dijk, C. N., Mueller-Gerbl, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+basic+science+of+the+subchondral+bone.">The basic science of the subchondral bone.</a> Knee Surgery, Sports, Traumatology, Arthrosclerosis. 18 (4), 419-433 (2010).</li><li>Milz, S., Putz, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+morphology+of+the+subchondral+plate+of+the+tibial+plateau.">Quantitative morphology of the subchondral plate of the tibial plateau.</a> Journal of Anatomy. 185, 103-110 (1994).</li><li>Blalock, D., Miller, A., Tilley, M., Wang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+instability+and+osteoarthritis.">Joint instability and osteoarthritis.</a> Clinical Medicine Insights: Arthritis and Musculoskeleton Disorders. 8, 15-23 (2015).</li><li>Waung, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+X-ray+microradiography+for+high-throughput+phenotyping+of+osteoarthritis+in+mice.">Quantitative X-ray microradiography for high-throughput phenotyping of osteoarthritis in mice.</a> Osteoarthritis Cartilage. 22 (10), 1396-1400 (2014).</li><li>Botter, S. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cartilage+damage+pattern+in+relation+to+subchondral+plate+thickness+in+a+collagenase-induced+model+of+osteoarthritis.">Cartilage damage pattern in relation to subchondral plate thickness in a collagenase-induced model of osteoarthritis.</a> Osteoarthritis Cartilage. 16 (4), 506-514 (2008).</li><li>Nalesso, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+calmodulin+kinase+II+activity+is+required+for+cartilage+homeostasis+in+osteoarthritis.">Calcium calmodulin kinase II activity is required for cartilage homeostasis in osteoarthritis.</a> Science Reports. 11 (1), 5682 (2021).</li><li>Ding, M., Christian Danielsen, C., Hvid, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+hyaluronan+on+three-dimensional+microarchitecture+of+subchondral+bone+tissues+in+guinea+pig+primary+osteoarthrosis.">Effects of hyaluronan on three-dimensional microarchitecture of subchondral bone tissues in guinea pig primary osteoarthrosis.</a> Bone. 36 (3), 489-501 (2005).</li><li>Kraus, V. B., Huebner, J. L., DeGroot, J., Bendele, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+OARSI+histopathology+initiative+-+recommendations+for+histological+assessments+of+osteoarthritis+in+the+guinea+pig.">The OARSI histopathology initiative - recommendations for histological assessments of osteoarthritis in the guinea pig.</a> Osteoarthritis Cartilage. 18, 35-52 (2010).</li><li>McNulty, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comprehensive+histological+assessment+of+osteoarthritis+lesions+in+Mice.">A comprehensive histological assessment of osteoarthritis lesions in Mice.</a> Cartilage. 2 (4), 354-363 (2011).</li><li>Glasson, S. S., Chambers, M. G., Van Den Berg, W. B., Little, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+OARSI+histopathology+initiative+-+recommendations+for+histological+assessments+of+osteoarthritis+in+the+mouse.">The OARSI histopathology initiative - recommendations for histological assessments of osteoarthritis in the mouse.</a> Osteoarthritis Cartilage. 18, 17-23 (2010).</li><li>Pritzker, K. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoarthritis+cartilage+histopathology:+grading+and+staging.">Osteoarthritis cartilage histopathology: grading and staging.</a> Osteoarthritis Cartilage. 14 (1), 13-29 (2006).</li><li>Mankin, H. J., Dorfman, H., Lippiello, L., Zarins, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+and+metabolic+abnormalities+in+articular+cartilage+from+osteo-arthritic+human+hips.+II.+Correlation+of+morphology+with+biochemical+and+metabolic+data.">Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips. II. Correlation of morphology with biochemical and metabolic data.</a> Journal of Bone and Joint Surgery American. 53 (3), 523-537 (1971).</li><li>Glasson, S. S., Blanchet, T. J., Morris, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+surgical+destabilization+of+the+medial+meniscus+(DMM)+model+of+osteoarthritis+in+the+129/SvEv+mouse.">The surgical destabilization of the medial meniscus (DMM) model of osteoarthritis in the 129/SvEv mouse.</a> Osteoarthritis Cartilage. 15 (9), 1061-1069 (2007).</li><li>Wang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcription+factor+Nfat1+deficiency+causes+osteoarthritis+through+dysfunction+of+adult+articular+chondrocytes.">Transcription factor Nfat1 deficiency causes osteoarthritis through dysfunction of adult articular chondrocytes.</a> Journal of Pathology. 219 (2), 163-172 (2009).</li><li>Zhang, M., Lu, Q., Budden, T., Wang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NFAT1+protects+articular+cartilage+against+osteoarthritic+degradation+by+directly+regulating+transcription+of+specific+anabolic+and+catabolic+genes.">NFAT1 protects articular cartilage against osteoarthritic degradation by directly regulating transcription of specific anabolic and catabolic genes.</a> Bone Joint Research. 8 (2), 90-100 (2019).</li><li>Zhang, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epigenetically+mediated+spontaneous+reduction+of+NFAT1+expression+causes+imbalanced+metabolic+activities+of+articular+chondrocytes+in+aged+mice.">Epigenetically mediated spontaneous reduction of NFAT1 expression causes imbalanced metabolic activities of articular chondrocytes in aged mice.</a> Osteoarthritis Cartilage. 24 (7), 1274-1283 (2016).</li><li>Rodova, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nfat1+regulates+adult+articular+chondrocyte+function+through+its+age-dependent+expression+mediated+by+epigenetic+histone+methylation.">Nfat1 regulates adult articular chondrocyte function through its age-dependent expression mediated by epigenetic histone methylation.</a> Journal of Bone and Mineral Research. 26 (8), 1974-1986 (2011).</li><li>Jackson, M. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Depletion+of+protease-activated+receptor+2+but+not+protease-activated+receptor+1+may+confer+protection+against+osteoarthritis+in+mice+through+extracartilaginous+mechanisms.">Depletion of protease-activated receptor 2 but not protease-activated receptor 1 may confer protection against osteoarthritis in mice through extracartilaginous mechanisms.</a> Arthritis and Rheumatology. 66 (12), 3337-3348 (2014).</li></ol>

The authors declare no competing conflicts of interest.

Measuring SCB thickening is an important component of histologic assessments of OA severity. Most existing OA grading systems focus mainly on cartilage changes15,16,17. A widely used murine osteoarthritic SCB thickness grading method that categorizes SCB thickening as mild, moderate, and severe is largely subjective, and its reliability has not been fully validated15. The present study has developed and v...

Osteoarthritis (OA), characterized radiographically by joint space narrowing due to the loss of articular cartilage, osteophytes, and subchondral bone (SCB) sclerosis, is the most common form of arthritis1,2. Although the role of peri-articular bone in the etiology of OA is not fully understood, osteophyte formation and SCB sclerosis are generally thought to be the results of the disease process rather than causative factors, but changes in peri-articular bone architecture/shape and biology may contribute to the development and progression of OA3,4. The development of an accurate and easily executed OA grading system, including SCB measurement, is critical for comparative studies among research laboratories and in evaluating the efficacy of therapeutic agents designed to prevent or attenuate OA progression.
SCB is built with a thin dome-like bone plate and an underlying layer of trabecular bone. The SCB plate is the cortical lamella, lying parallel to and immediately under the calcified cartilage. Small branches of arterial and venous vessels, as well as nerves, penetrate through the channels in the SCB plate, communicating between the calcified cartilage and the trabecular bone. The subchondral trabecular bone contains blood vessels, sensory nerves, bone marrow and is more porous and metabolically active than the SCB plate. Therefore, SCB exerts shock-absorbing and supportive functions and is also important for cartilage nutrient supply and metabolism in normal joints5,6,7,8.
SCB thickening (in histology) and sclerosis (in radiography) are the major hallmarks of OA and key research areas of OA pathophysiology. Measuring SCB thickening is an important component of histologic assessments of OA severity. Previously reported digital microradiography for measuring rodent SCB mineral density9 as well as micro-computed tomography (micro-CT) based quantitative SCB measurement in rodent models of OA10,11,12,13 have improved our understanding of SCB structure and the role of SCB changes in OA pathophysiology. SCB area and thickness has also been quantified with histological slides using a sophisticated computer system with specific and expensive bone histomorphometry software14. Nevertheless, visual estimate-based semi-quantitative OA grading systems, including SCB thickening grading, are more widely used than micro-CT at the present time because the grading systems are easy to use, particularly for screening numerous histologic images. However, most existing OA grading systems focus mainly on cartilage changes15,16,17. A widely used osteoarthritic SCB thickness grading method that categorizes SCB thickening as mild, moderate, and severe is largely subjective, and its reliability has not been fully validated15. A reliable and easily executed step-by-step osteoarthritic SCB thickness measurement protocol is either not fully developed or un-standardized.
This study aimed to develop a reproducible, sensitive, and easily executed protocol to quantitatively measure the SCB thickness in a mouse model of OA. Our rigorous measurement tests and statistical analysis demonstrated that this ImageJ software-assisted quantitative measurement protocol could quantify the SCB thickness in both normal and osteoarthritic knee joints. The newly developed protocol is reproducible and more sensitive to mild SCB changes than the widely used visual grading systems. It can be used for detecting early osteoarthritic SCB changes and for assessing in vivo efficacy of OA treatments in concert with OA cartilage grading.

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			<td>Safranin-O</td>
			<td>Sigma-Aldrich</td>
			<td>S8884</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast green</td>
			<td>Sigma-Aldrich</td>
			<td>F7252</td>
			<td></td>
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			<td>Hematoxylin</td>
			<td>Sigma-Aldrich</td>
			<td>GHS216</td>
			<td></td>
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			<td>Eosin</td>
			<td>Sigma-Aldrich</td>
			<td>E4382</td>
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			<td>illustrator</td>
			<td>Adobe</td>
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software-assisted quantitative measurement of osteoarthritic subchondral bone thickness

Subchondral bone thickening and sclerosis are the major hallmarks of osteoarthritis (OA), both in animal models and in humans. Currently, the severity of the histologic subchondral bone thickening is mostly determined by visual estimation based semi-quantitative grading systems. This article presents a reproducible and easily executed protocol to quantitatively measure subchondral bone thickness in a mouse model of knee OA induced by destabilization of the medial meniscus (DMM). This protocol utilized ImageJ software to quantify subchondral bone thickness on histologic images after defining a region of interest in the medial femoral condyle and the medical tibial plateau where subchondral bone thickening usually occurs in DMM-induced knee OA. Histologic images from knee joints with a sham procedure were used as controls. Statistical analysis indicated that the newly developed quantitative subchondral bone measurement system was highly reproducible with low intra- and inter-observer variabilities. The results suggest that the new protocol is more sensitive to subtle or mild subchondral bone thickening than the widely used visual grading systems. This protocol is suitable for detecting both early and progressing osteoarthritic subchondral bone changes and for assessing in vivo efficacy of OA treatments in concert with OA cartilage grading.

Reproducibility comparison between visual estimate grading and ImageJ-assisted quantitative measurement: 
SCB thickness in 48 regions of interest (ROI) (24 MFC and 24 MTP), defined from a mid-section of each knee from 24 knees/animals was scored by three independent individuals using the existing 0-3 visual scoring scheme as described in the literature15,23, where 0 = normal (no SCB thickening), 1 = mild, 2 = moderate, and 3 = severe SCB thi...

Watch this Scientific Journal Video about Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness at JoVE.com

Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness

This methodology article presents a software-assisted quantitative measurement protocol to quantify histologic subchondral bone thickness in murine osteoarthritic knee joints and normal knee joints as controls. This protocol is highly sensitive to subtle thickening and is suitable for detecting early osteoarthritic subchondral bone changes.

Subchondral bone thickening and sclerosis are the major hallmarks of osteoarthritis (OA), both in animal models and in humans. Currently, the severity of ...

Subchondral bone thickening, or sclerosis, is one of the hallmarks of osteoarthritis, both in animal models and in humans. Currently, the severity of histologic subchondral bone thickening is mostly determined by visual estimation based on semi-quantitative grading systems. This study aim to develop a reproducible and easily executed protocol to quantitatively measure subchondral bone thickness in a mouse model of knee OA induced by destabilization of the medial meniscus.We created a mouse model for knee osteoarthritis by surgical destabilization of the medial meniscus which is performed under surgical microscope and the sterile condition. The histological process of mouse knee joints include tissue fixation, decalcification, trimming, processing, embedding, sectioning, and staining, followed by microscopic imaging. The image on the screen shows mouse knee osteoarthritis with articular cartilage lesions, osteophyte formation, and subchondral bone thickening Quantitative measurement of osteoarthritic subchondral bone with ImageJ software.Download ImageJ from imagej.nih.gov/ij. Open ImageJ. Click the File tab and then click Open option to open the histologic image.Find the file directory address, select the picture file, and click Open. Use the straight line tool to sketch one unit of length, a micrometer, and click Analyze, then Set Scale. Set the known distance and the pixel aspect ratio to one and click Ok.ImageJ can convert the pixel length to the unit length, a micrometer.Set the measured factor to area. Click Analyze then Set Measurement and check Area and Limit to Threshold box under the new window. This step sets ImageJ to measure parameter area within selected threshold.Defined total subchondral bone area of interest as shown in radio which covers the subchondral cortical plate and a portion of the underlying trabecular bone adjacent to cortical plate. Sketch the outline of total subchondral bone area by using the selection tool under the main window of image. The selection tools gives the system a threshold to limit the measurement after threshold being selected.Click Analyze then Measure. A result window with area measurement will open. Click Edit then Clear Outside to exclude the area outside total subchondral bone area.Only total subchondral bone area is visible after clicking Clear Outside option. Click Image then Adjust then Color Threshold to open the threshold color window. Click Original at the bottom of threshold color window to restore picture to original status.Use selection tools to draw a small box in the bone substance region. Click Sample Option at the bottom of window to define the bone substance area. Selected bone substance area will turn to red.Click Select at the bottom of threshold color window to create area measurement threshold. Click Analyze then Measure in ImageJ main menu. The bone substance area measurement result will show on result window.Save the data of total subchondral bone area and bone substance area. The inter and intraobserver variability and the reproducibility were determined by Pearson's correlation coefficient analysis. The significance of difference between study groups were determined by using Student t-test or one-way ANOVA, followed by post-hoc test.This figure shows upper and lower panels. The upper panel shows photomicrographs of histologic images from Sham and DMM groups for visual estimate-based subchondral bone grading. The lower panels show photomicrographs of histologic images from Sham and DMM groups for ImageJ-assisted, quantitative subchondral bone measurement.The boxes outlined with a dotted yellow line made with Adobe Illustrator defines the total subchondral bone area of interest. The area of bone substance within the boxes is highlighted in orange. Remarkable subchondral bone thickening in the medial femoral condyle and medial tibial plateau can be quantified using ImageJ software.In this figure, interobserver variation tests indicate a high reproducibility between observers for both the first and second measurements of subchondral bone thickness in the medial tibial plateau and the medial femoral condyle regions of interest. In this figure, intraobserver variation tests indicate a high reproducibility between the first and second subchondral bone thickness measurements in the medial tibial plateau and medial femoral condyle regions of interest. Table 1 shows comparative analysis of reproducibility between the visual grading and ImageJ-assisted quantitative measurement of subchondral bone thickness.Correlation coefficient test suggests that the quantitative measurement was relatively more reproducible than the visual grading system. This figure shows comparative sensitivity analysis of visual grading and ImageJ-assisted quantitative measurement of subchondral bone thickness in the medial femoral condyle and the medial tibial plateau. The histologic images for visual estimate grading were divided into three groups.The quantitative subchondral bone thickness value from all three observers for the DMM images with a zero visual score were significantly higher than that of the Sham images with a zero visual score, indicating that the quantitative measurement is more sensitive than the visual grading to mild subchondral bone thickening. The newly developed protocol for quantitative measurement of osteoarthritic subchondral bone thickness is more sensitive to mild subchondral bone changes than the widely used visual grading systems. And this protocol can be used for detecting early osteoarthritic subchondral bone changes and for assessing in vivo efficacy of osteoarthritis treatments in concert with osteoarthritis cartilage grading.

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JoVE Journal

Medicine

2.8K Görüntüleme.  University of Kansas Medical Center. Subkondral kemik kalınlaşma veya skleroz, hem hayvan modellerinde hem de insanlarda osteoartritin ayırt edici özelliklerinden biridir. Günümüzde histolojik subkondral kemik kalınlaştırmasının şiddeti çoğunlukla yarı nicel not sistemlerine dayalı görsel tahmin ile belirlenmektedir. Bu çalışma, medial menisküslerin istikrarsızlaşmasıyla indüklenen diz OA'sının fare modelinde subkondral kemik kalınlığını nicel olarak ölçmek için tekrarlanabilir ve kolayca yür...