# Protocol required for Immunofluorescence in Bone Paraffin sections

**URL:** <https://scientistsolutions.discourse.group/t/protocol-required-for-immunofluorescence-in-bone-paraffin-sections/653>\
**Category:** Cell Anatomy / Physiology\
**Created:** [January 13, 2025, 12:22pm UTC](https://scientistsolutions.discourse.group/t/protocol-required-for-immunofluorescence-in-bone-paraffin-sections/653 "2025-01-13T12:22:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Navneet](https://avatars.discourse-cdn.com/v4/letter/n/8e8cbc/32.png) [@Navneet](https://scientistsolutions.discourse.group/u/Navneet)\
**Post date:** [January 13, 2025, 12:22pm UTC](https://scientistsolutions.discourse.group/t/protocol-required-for-immunofluorescence-in-bone-paraffin-sections/653/1 "2025-01-13T12:22:56Z")

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Hi, Does someone have a protocol about immunofluorescence in bone paraffin-embedded sections? Especially, I would like to know use which method for antigen retrieval?

Thanks

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**Author:** ![Biographix](https://avatars.discourse-cdn.com/v4/letter/b/b9bd4f/32.png) [@Biographix](https://scientistsolutions.discourse.group/u/Biographix)\
**Post date:** [January 13, 2025, 12:27pm UTC](https://scientistsolutions.discourse.group/t/protocol-required-for-immunofluorescence-in-bone-paraffin-sections/653/2 "2025-01-13T12:27:09Z")

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Immunofluorescence (IF) on paraffin-embedded bone sections can be challenging due to the hard nature of the tissue and the need for effective antigen retrieval. Important Points to Remember are

- **Decalcification** : Ensure that bone tissue is adequately decalcified before paraffin embedding. Over-decalcification can damage antigenicity, while insufficient decalcification can make sectioning difficult.
- **Control Sections** : Include negative controls (no primary antibody) to assess background staining.
- **Optimization** : Antibody concentrations and retrieval conditions may require optimization based on the specific antigen and tissue.

Here is a detailed protocol tailored for bone tissue:

#### **Materials**

- Paraffin-embedded bone sections (cut at 5-7 µm)
- Xylene, ethanol series (100%, 95%, 70%), and distilled water
- Phosphate-buffered saline (PBS)
- Heat-induced antigen retrieval (HIER) solution (e.g., Citrate buffer, pH 6.0 or Tris-EDTA buffer, pH 9.0)
- Blocking solution (5% BSA or normal serum in PBS)
- Primary antibody (specific to target antigen)
- Secondary antibody (fluorophore-conjugated)
- Mounting medium with DAPI or another nuclear stain
- Coverslips
- Fluorescence microscope

#### **Protocol**

### **1. Deparaffinization and Rehydration**

1. **Deparaffinization** :

- Place slides in a series of xylene baths:
  - Xylene 1: 5 minutes
  - Xylene 2: 5 minutes
  - Xylene 3: 5 minutes

1. **Rehydration** :

- Immerse slides in a series of ethanol baths to rehydrate:
  - 100% ethanol: 5 minutes
  - 95% ethanol: 5 minutes
  - 70% ethanol: 5 minutes

- Rinse slides in distilled water for 5 minutes.

### **2. Antigen Retrieval (Critical Step)**

**Method** : Heat-Induced Epitope Retrieval (HIER) is the preferred method for bone tissues to unmask epitopes that are cross-linked during formalin fixation. Choose one of the following buffers based on the target antigen:

- **Citrate Buffer (pH 6.0)**: For most proteins.
- **Tris-EDTA Buffer (pH 9.0)**: For antigens that require more stringent conditions.

**Procedure** :

1. Preheat the antigen retrieval buffer in a microwave, water bath, or pressure cooker.
2. Place slides in a slide rack and immerse in the preheated buffer.
3. Heat the slides:

- **Microwave** : 5-10 minutes at 90-100°C.
- **Water bath** : 20 minutes at 95°C.
- **Pressure cooker** : 3-5 minutes at full pressure.

1. Allow slides to cool at room temperature in the buffer for 20-30 minutes.
2. Rinse slides in PBS to remove residual buffer.

### **3. Blocking**

1. Incubate slides in blocking solution (5% BSA or 10% normal serum in PBS) for 1 hour at room temperature to reduce non-specific binding.

### **4. Primary Antibody Incubation**

1. Dilute the primary antibody in PBS with 1% BSA.
2. Apply the antibody to the sections and incubate overnight at 4°C in a humidified chamber.

### **5. Washing**

1. Wash slides in PBS three times for 5 minutes each to remove unbound primary antibody.

### **6. Secondary Antibody Incubation**

1. Dilute the fluorophore-conjugated secondary antibody in PBS with 1% BSA.
2. Apply the secondary antibody and incubate for 1 hour at room temperature in the dark to protect from light.

### **7. Washing**

1. Wash slides in PBS three times for 5 minutes each in the dark.

### **8. Counterstaining (Optional)**

1. Apply a mounting medium with DAPI or another nuclear stain.
2. Place a coverslip over the section and allow the medium to set.