Application of Infrared Thermography to the Detection of Changes in Interscapular Brown Adipose Tissue Temperature and Analysis of Some Blood Biochemical and Behavioural Parameters in BALB/C and C57BL/6 Mouse Strains

Abstract

Brown adipose tissue (BAT) has received renewed interest as a potential treatment target for obesity and comorbidities due to its thermogenic activity capacity and contribution to energy expenditure. Murine models are among the commonest preclinical models for studying human disease, including BAT studies. C57BL/6 and BALB/c are the two most commonly used mouse strains, however, different strains manifest significant behavioural differences, levels of sociability, emotionality, exercise response, respond differently to severe spinal cord injury, show differences in susceptibility to dietinduced obesity and insulin resistance, etc. To gain a broader understanding of the peculiarities, this study aimed to investigate the effect of age, strain and gender on interscapular BAT temperature changes and to analyse some blood biochemical and behavioural parameters in the aforementioned strains. The age of the mice (5–8 weeks) did not influence the interscapular BAT area temperature. The mean temperatures of the maximum (Tmax) and the average temperatures (Tisoth) in the BALB/c mice were by 0.46 °C (P<0.001) and by 0.37 °C (P<0.001) higher than in the C57BL/6 mice. In addition, the gender of the mice also modulated the BAT area temperature, causing an increment of 0.29 °C (P<0.001) and 0.21 °C (P<0.05) in Tmax and Tisoth temperatures of males, respectively. The difference in mean glucose, cholesterol and triglyceride levels between the BALB/c and C57BL/6 strains was not substantial. Behavioural analyses disclosed a statistically insignificant distribution of grooming activities in male BALB/c and C57BL/6 mice and significant (P<0.001) differences in female mice. Collectively, our findings revealed that infrared thermography can be successfully used to measure interscapular BAT temperature in mice in vivo, and that mouse strain and gender can alter BAT measurements.