Method to select mice in the steady state for biological studies.

Area of Science:

• Veterinary Medicine
• Immunology
• Animal Research

Background:

• Accurate leukocyte counts are vital in biomedical research to assess the impact of substances.
• Repeated blood sampling in mice is often necessary for longitudinal studies.
• Stress from experimental procedures can significantly alter leukocyte numbers.

Purpose of the Study:

• To evaluate orbital sinus blood collection as a method for repeated mouse sampling.
• To investigate the impact of stress on leukocyte counts in mice.
• To compare leukocyte counts from different blood collection sites (orbital sinus, tail, heart).

Main Methods:

• Blood collection from the orbital sinus for repeated sampling in mice.
• Implementing single-stressor experimental designs to minimize animal stress.
• Comparative analysis of leukocyte subsets (monocytes, lymphocytes, granulocytes) from various blood sources.
• Utilizing 5 specific pathogen-free mouse strains for comparative studies.

Main Results:

• Orbital sinus blood collection is a satisfactory method for repeated sampling in mice.
• Two stress-inducing procedures on the same day alter leukocyte numbers, while a single stressor per day maintains stable counts.
• Systematic differences in mean leukocyte numbers were observed between orbital sinus, tail, and heart blood.
• Statistically significant variations in monocytes, lymphocytes, and granulocytes were found in orbital blood across five mouse strains.

Conclusions:

• Orbital sinus blood collection is a viable technique for longitudinal leukocyte monitoring in mice.
• Experimental design should minimize daily stressors to ensure reliable leukocyte count data.
• Differences in leukocyte profiles exist depending on the blood collection site and mouse strain.