Isolation-induced renal functional changes in rats from four breeders

Area of Science:

• Toxicology
• Renal Physiology
• Animal Models

Background:

• Accurate assessment of drug-induced nephrotoxicity requires reliable renal function estimation.
• Standard protocols often involve individual housing in metabolic cages for urine collection, potentially inducing stress.
• The impact of isolation on renal function can vary based on the animal's source.

Purpose of the Study:

• To compare the effects of 4-day isolation on renal function in Sprague-Dawley rats from four different breeders.
• To identify if rat origin influences the physiological response to isolation.
• To inform best practices for preclinical studies involving renal function assessment.

Main Methods:

• Four groups of Sprague-Dawley rats from distinct breeders (Harlan, Charles River, BioLab, TIMCO) were housed individually for 4 days.
• Parameters measured included body weight, urine flow rate, serum creatinine, creatinine clearance, fractional sodium reabsorption, and fractional potassium excretion.
• Baseline and post-isolation values were compared within and between groups.

Main Results:

• No significant weight loss differences were observed between groups post-isolation.
• Urine flow rate significantly decreased in TIMCO and Charles River rats compared to baseline and other groups.
• TIMCO rats showed significantly increased serum creatinine and decreased creatinine clearance post-isolation; Charles River rats also showed decreased creatinine clearance.
• Fractional sodium reabsorption was reduced in TIMCO rats.

Conclusions:

• Animal isolation significantly alters renal function in TIMCO Sprague-Dawley rats, impacting urine flow and creatinine clearance.
• The source of Sprague-Dawley rats is a critical variable to consider in studies assessing renal function.
• Researchers must account for isolation duration and animal origin to ensure the validity of renal function assessments in preclinical studies.