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Methods for Evaluating Articular Cartilage Quality
Published in Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi, Articular Cartilage, 2017
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi
Histologically, general collagen staining can take advantage of the protein’s fibril organization, while collagen typing occurs through immunohistochemical staining. For instance, sirius red, used in a saturated solution of picric acid (also known as picrosirius red), stains collagen fibers pink to red as the dye binds to collagen helices (Figure 5.14). Due to the aspect ratio of the dye molecule, trapping accentuates alignment, especially under polarized light (Junqueira et al. 1979), where binding degree can be assessed as lighter-to-heavier staining transitions from yellow to green. Other stains, such as aniline blue, can be used to stain collagen, and, while polarized light microscopy for collagen alignment can also be performed without staining, the effect for observing alignment is not as dramatic as when sirius red is used. SEM and TEM can also be used to visualize collagen fiber thickness and orientation, although these, like histology, are destructive methods.
Collagens in Nervous Tissue
Published in Marcel E. Nimni, Collagen, 1988
Although all three layers are composed of collagen with similar microscopic appearance, they differ in chemical composition and ultrastructural appearance.4–7 The epineurium is composed of compactly arranged, coarse type I collagen; it is nonargyrophilic and exhibits strong birefringence subsequent to staining with sirius red and picric acid.8
Cardiac Hypertrophy, Heart Failure and Cardiomyopathy
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
There are no morphological correlates that will tell the pathologist using light microscopy that the borderline between hypertrophy and failure has been crossed. Generally, there will be myocyte degeneration with variation in size with reduction in transverse diameter and attenuation of myocytes and vacuolization with surrounding collagen often replacing myocytes (Figs. 5.11, 5.12) The nuclei also become distorted in shape. A major change in the myocardium in failure is the increase in interstitial fibrosis. In hypertrophy, an increase in the number of interstitial fibroblastic cells occurs and the concentration of collagen rises. The surface area of the myocardium staining as collagen may reach 25% in severe hypertrophy, and is distributed both as coarse strands and a more diffuse fine interstitial fibrosis. As hypertrophy increases, a point is reached when hyperplasia of the interstitial cells and collagen production becomes disproportionate to the increase in myocyte mass. At its extreme, in hearts weighing over 750 g, all subsequent increase in mass may be collagen. The degree of interstitial fibrosis is significantly greater in pressure-overload hypertrophy such as aortic valve stenosis or hypertension than in volume-overload such as aortic regurgitation. Studies which compare the amounts of interstitial fibrosis in the myocardium with the degree of functional disability in the subject show that there is a direct correlation of increasing fibrosis with declining myocardial function. The degree of inter-subject and inter-cause variation, however, is so great that a pathologist cannot look at a myocardial section and categorically say that chronic HF is present. The most widely used methods of measuring myocardial fibrosis is by surface area in sections stained to differentiate myocytes from collagen. Sirius red stains rather more collagen than the Van Gieson method and computer-generated software packages are available for slide scanning and collagen quantification. Another morphological change associated with cardiac failure is a reduction in the density of myofibrils within the myocyte leading to vacuolization. This myocyte change is probably a late result of HF rather than its cause and is concentrated in the subendocardium (Fig. 5.12).
JianPi-QingHua formula attenuates nonalcoholic fatty liver disease by regulating the AMPK/SIRT1/NF-κB pathway in high-fat-diet-fed C57BL/6 mice
Published in Pharmaceutical Biology, 2023
Jing Tian, Mengjie Cai, Shenyi Jin, Qingguang Chen, Jiahui Xu, Qiuyue Guo, Zihui Yan, Xu Han, Hao Lu
Subsequently, we examined whether JPQH ameliorated liver injury induced by HFD. In this study, H&E staining showed that the mice in the HFD group had excessive accumulation of lipid droplets (red arrow) and inflammatory cell infiltration (black arrow), and all of the changes were ameliorated after JPQH supplementation (Figure 4(A)). According to the pathological score of liver injury (Nelson et al. 2011; Ding et al. 2020), NAFLD lesion severity in the JPQH group was also significantly reduced (p < 0.01) (Figure 4(B)). However, Sirius red staining showed there was no significant difference between the groups (Figure 4(C,D)), suggesting that this stage had not yet developed into liver fibrosis. Elevated hepatic AST and ALT activity was also the hallmark of liver damage. JPQH attenuated hepatic AST and ALT activity in HFD group (Figure 4(E,F)). As indicated by these results, JPQH mitigated the NAFLD induced by HFD.
ARRDC3 inhibits liver fibrosis and epithelial-to-mesenchymal transition via the ITGB4/PI3K/Akt signaling pathway
Published in Immunopharmacology and Immunotoxicology, 2023
Bingling Zhang, Feng Wu, Pingping Li, Haiding Li
Liver tissues were fixed with 4% paraformaldehyde, embedded in paraffin, and 4 μm sections were obtained using a Leica microtome (Leica, Wetzlar, Germany). The results of HE staining were determined as follows: nuclei were blue, cytoplasm and other tissue components showed varying shades of red, myofibers were red, erythrocytes were vermilion, and eosinophilic granules were orange. Masson’s staining criteria were a blue color for collagen, red color for cytoplasm, myofibrils, and red cells, and a blue-brown color for nuclei. For Sirius red staining, type I collagen fibers were tightly packed and showed strong birefringence as yellow or red fibers. Type II collagen showed weak birefringence with a loose network of multiple colors. Type III collagen fibers were sparsely networked and showed weak birefringence as fine green fibers. Type IV collagen fibers showed a weak birefringence of the basement membrane and were yellowish. In this study, case results were determined by randomly selecting images from six liver sections of three rats per group (n = 10), and the results were interpreted by two independent pathologists.
Biomechanical Characterization of a New Acellular Dermal Matrix for Oral Soft Tissue Regeneration
Published in Journal of Investigative Surgery, 2022
Andreas Pabst, Keyvan Sagheb, Sebastian Blatt, Kawe Sagheb, Saskia Schröger, Stefan Wentaschek, Sven Schumann
Samples of ASG and ADM were fixed in buffered formaldehyde solution (4%) and embedded in paraffin. Sections were stained with hematoxylin and eosin (H&E), Heidenhain’s Azan, Sirius red and Weigert’s elastic according to standard protocols. Briefly, sections were deparaffinized in xylol and rehydrated in ethanol of decreasing concentrations. H&E staining was performed with hematoxylin (Sigma-Aldrich, St. Louis, Missouri, US) and eosin (Sigma-Aldrich) after flushing in distilled water. For Heidenhain’s Azan staining, a staining kit was used (Cat No. 12079, MORPHISTO Ltd., Offenbach am Main, Germany). Sirius red staining was conducted using Sirius red F3B (Chroma, Waldeck GmbH & Co. KG, Münster, Germany), and picric acid (Sigma-Aldrich). For Weigert’s elastic staining resorcin-fuchsin (Chroma) and nuclear fast red (Sigma-Aldrich) were used. After staining, a dehydration of ethanol in increasing concentration and treatment in xylol followed. Histological sections were imaged with a Leica MS 5 tripod (Leica Microsystems, Germany) and a JVC KY-F75U C mount digital camera (JVC, Yokohama, Japan) [14].