Fresolimumab

Fibrosis and collagen morphometry is based on the quantitative visualization of fibrillar collagen deposition in tissue sections using histochemical stains such as Sirius Red (Picrosirius Red) or Masson's trichrome, followed by image-based or polarization-enhanced analysis to estimate collagen proportional area as a surrogate of extracellular matrix accumulation during fibrotic remodeling. Sirius Red combined with polarized light microscopy enhances detection of collagen fibers due to birefringence properties, enabling more specific visualization of collagen type I and III fibrils compared to conventional bright-field histology, while whole-section or region-restricted digital morphometry reduces field-selection bias in fibrosis assessment. Alternative quantitative approaches include second harmonic generation (SHG) and two-photon excited fluorescence microscopy, which enable label-free detection of fibrillar collagen and have been validated against histological staining and biochemica

By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.

Sirius Red or picrosirius red staining is a histochemical method for visualizing collagen-rich extracellular matrix in tissue sections, and collagen fibers are detected as red-stained structures under bright-field microscopy with enhanced birefringence under polarized light. Picrosirius red is useful for assessing total collagen organization, distribution, and fibrosis burden, but polarized color should not be interpreted as a definitive collagen type I versus type III readout because color is affected by fiber orientation, thickness, and packing.

Mesenchymal stromal/stem cells can be induced toward an osteoblast-like lineage in vitro by culture in osteogenic medium containing dexamethasone, ascorbic acid or ascorbate-2-phosphate, and β-glycerophosphate; the differentiation process is commonly evaluated by alkaline phosphatase activity, osteogenic marker expression, collagenous matrix formation, and calcium-rich matrix mineralization. The main readouts are alkaline phosphatase activity as an early osteogenic marker and Alizarin Red S staining as a calcium-deposit readout for mineralized extracellular matrix; Alizarin Red S can be inspected microscopically or extracted and measured colorimetrically at 405 nm.

Masson’s Trichrome (collagen/trichrome staining) is a histological technique that differentially stains tissue compartments using sequential acidic dyes to distinguish collagen from muscle and cytoplasmic components based on dye affinity and tissue permeability differences, enabling visualization of fibrosis and connective tissue architecture in histological sections. The classical formulation typically uses Weigert's iron hematoxylin for nuclear staining, Biebrich scarlet-acid fuchsin for cytoplasm and muscle, and aniline blue (or light green variants) for collagen, producing a characteristic blue/green collagen signal contrasted against red cytoplasm and dark nuclei. The staining principle relies on selective displacement of smaller dye molecules by larger anionic dyes in collagen-rich regions under controlled acidified conditions, which enhances collagen-specific dye retention. This property makes the method widely used for fibrosis assessment in organs such as heart, liver, lung, a

Inhalation toxicity studies expose rodents to a controlled aerosol, vapor, gas, or smoke atmosphere and assess respiratory and systemic toxicity using exposure-atmosphere characterization, clinical observations, body and organ weights, bronchoalveolar lavage fluid, histopathology, blood chemistry, hematology, and, when included, molecular endpoints such as transcriptomics, proteomics, lipidomics, or tissue burden analysis. The primary biological readouts are airway irritation, pulmonary inflammation, cytotoxicity, altered surfactant or lipid homeostasis, impaired particle clearance, and tissue remodeling, reflected by BALF cell differentials, BALF protein, LDH, phosphatase activities, cytokines, lung weight, microscopic respiratory-tract lesions, and retained lung burden.