Brain perfusion fixation in male pigs using a safer closed system

Area of Science:

• Veterinary Anatomy
• Histology Techniques
• Animal Research Models

Background:

• Standard tissue fixation methods are established for rodents but lack efficient protocols for large animals.
• In situ perfusion fixation offers superior tissue preservation compared to immersion methods.
• Large animal models are crucial for translational research, necessitating robust anatomical preservation techniques.

Purpose of the Study:

• To present a simple, safe, and effective in situ brain perfusion fixation technique for large animals.
• To establish a closed system for perfusion fixation, minimizing operator exposure to hazardous chemicals.
• To optimize perfusion parameters for efficient fixation and tissue extraction in porcine models.

Main Methods:

• Developed a closed-system perfusion technique using cervical vessels (common carotid artery and external jugular vein) for inflow and outflow in pigs.
• Utilized a peristaltic pump for controlled perfusion with heparinised saline followed by buffered formaldehyde.
• Optimized perfusion rate (0.20 L/min) and duration (20-30 minutes) using approximately 5 liters of fixative.
• Extracted and processed brain, cerebellum, and brainstem specimens for histological analysis.

Main Results:

• Achieved successful in situ brain perfusion fixation in 34 porcine subjects without fixative leakage.
• Demonstrated minimization of operator exposure to formaldehyde and associated hazards.
• Obtained sufficiently hardened specimens for extraction and high-quality tissues suitable for histological analysis.
• The technique proved user-friendly and adaptable for other head, face, and neck tissues.

Conclusions:

• The presented technique provides a user-friendly, closed-system method for in situ brain perfusion fixation in large animals.
• This approach enhances operator safety and yields high-quality histological specimens.
• The method is adaptable and offers significant advantages over traditional fixation techniques for large animal research.