Sex Differences in Physiological Acclimatization after Transfer in Wistar Rats

Area of Science:

• Laboratory animal science
• Animal welfare
• Research methodology

Background:

• Laboratory animals are typically vendor-bred and transferred to research facilities.
• Transfer procedures can introduce unintended variables affecting research results.
• Understanding the impact of animal transfer is crucial for data integrity.

Purpose of the Study:

• To compare physiological and behavioral parameters in Wistar rats before and after external and internal transfers.
• To investigate the effects of transfer on body weight, plasma corticosterone, heart rate, blood pressure, and locomotor activity.
• To account for sex differences in stress responsivity during transfer acclimatization.

Main Methods:

• Wistar rats (male and female) were monitored for physiological and behavioral changes.
• Parameters assessed included body weight, plasma corticosterone, heart rate, blood pressure, and locomotor activity.
• Comparisons were made between transferred and non-transferred animals, and between sexes and light phases.

Main Results:

• External transfer decreased body weight and increased plasma corticosterone and activity.
• Heart rate responses to transfer differed between sexes: increased in females, decreased in males.
• Physiological and behavioral parameters varied significantly between sexes and light phases, indicating sex-specific acclimatization.

Conclusions:

• Acclimatization following animal transfer is sex-specific.
• Researchers must consider sex differences when determining appropriate acclimatization periods.
• Recommended acclimatization: at least 8 days for males and 2 weeks for females post-external transfer, with internal transfer 2 days prior to experiments.