Sirius Red Stain Service: High-Contrast Collagen Visualization for Fibrosis Research 

At iHisto, we offer expert Picro-Sirius Red staining to detect and quantify collagen fibers in histological tissues. Optimized for both brightfield and polarized light microscopy, our Sirius Red protocol provides precise, reproducible collagen assessment for fibrosis, ECM remodeling, and pathology research.

🧪 Overview 

The Sirius Red stain binds specifically to collagen types I and III, making it a gold-standard technique for evaluating:

• Fibrosis progression

• Cardiac and renal remodeling

• Tumor stromal collagen deposition

• ECM response to therapeutic interventions

At iHisto, we ensure strong red staining of collagen with clean background contrast and polarized imaging compatibility for enhanced fiber analysis.

⚙️ How Sirius Red Staining Works

Sirius Red is an anionic dye that binds to basic side chains of collagen molecules. When combined with picric acid, it provides:

Brightfield Microscopy Results:

• Collagen (type I/III) → red

• Muscle/cytoplasm → yellow

• Nuclei (with hematoxylin) → black

Polarized Light Results:

• Type I collagen → yellow/orange (thicker fibers)

• Type III collagen → green (finer fibers)

This birefringence-based color shift allows subtype distinction and quantitative analysis of collagen architecture.

🧬 Step-by-Step Staining Process 

1. Fixation & Sectioning – FFPE tissue cut at 4–6 µm

2. Deparaffinization & Hydration – Slides processed into water

3. Sirius Red Staining – Incubated in Sirius Red + saturated picric acid

4. Differentiation & Washing – Acidified water removes background

5. Counterstaining – Hematoxylin applied for nuclei

6. Dehydration & Coverslipping – Prepared for brightfield or polarized light

🔬 Applications of Sirius Red Staining 

Sirius Red is essential for collagen visualization in:

• Liver fibrosis (e.g., NASH, cirrhosis – METAVIR/Ishak scoring)

• Cardiac fibrosis after infarction or hypertrophy

• Renal sclerosis in nephropathy models

• Lung fibrosis (e.g., bleomycin models, IPF)

• Tumor ECM research – stromal collagen quantification

• Drug efficacy studies – antifibrotic treatment response

✅ Why Choose iHisto’s Sirius Red Stain Service

• ✅ Clear collagen type I/III visualization

• ✅ Compatible with polarized microscopy for enhanced subtype contrast

• ✅ Ideal for fibrosis scoring across multiple organs

• ✅ High-quality slides for manual or AI-driven quantification

• ✅ Optional whole-slide scanning and secure HistoCloud delivery

• ✅ Pathologist annotation or review available upon request

We support academic labs, CROs, and biotech companies with rigorous Sirius Red results tailored for fibrosis and ECM studies.

❓ FAQs

• What does Sirius Red stain detect?
  It targets collagen fibers, especially types I and III, for visualization and fibrosis analysis.

• Can it distinguish collagen subtypes?
  Yes. Under polarized light, type I appears yellow/orange, and type III appears green.

• Is this stain used for liver fibrosis?
  Absolutely — it’s a standard for quantifying collagen deposition in chronic liver disease models.

• Do you scan and digitize Sirius Red slides?
  Yes. We provide high-resolution whole-slide imaging with secure delivery for AI or pathologist review.

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📩 Request a Quote or Consultation 

Need precise collagen assessment for fibrosis or ECM research? iHisto’s Sirius Red staining service delivers consistent, high-contrast slides for confident analysis — from drug screening to pathology scoring.

👉 Request a Quote or email us at info@ihisto.io