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Phenotypic sexual dimorphism in response to dietary fat manipulation in C57BL/6J mice.

Citation
Casimiro, I., et al. “Phenotypic Sexual Dimorphism In Response To Dietary Fat Manipulation In C57Bl/6J Mice.”. Journal Of Diabetes And Its Complications, p. 107795.
Center Indiana University University of Chicago
Multicenter
Multicenter
Author Isabel Casimiro, Natalie D Stull, Sarah A Tersey, Raghavendra G Mirmira
Keywords C57BL/6J, high fat diet, obesity, Sexual dimorphism, Western diet
Abstract

BACKGROUND: Obesity and the metabolic syndrome are increasingly prevalent in society and their complications and response to treatment exhibit sexual dimorphism. Mouse models of high fat diet-induced obesity are commonly used for both mechanistic and therapeutic studies of metabolic disease and diabetes. However, the inclusion of female mammals in obesity research has not been a common practice, and has resulted in a paucity of data regarding the effect of sex on metabolic parameters and its applicability to humans.

METHODS: Here we analyzed male and female C57BL/6 J mice beginning at 4 weeks of age that were placed on a low-fat diet (LFD, 10% calories from fat), a Western Diet (WD, 45% calories from fat), or a high fat diet (HFD, 60% calories from fat). Assessments of body composition, glucose homeostasis, insulin production, and energy metabolism, as well as histological analyses of pancreata were performed.

RESULTS: Both male and female C57BL/6 J mice had similar increases in total percent body weight gain with both WD and HFD compared to LFD, however, male mice gained weight earlier upon HFD or WD feeding compared to female mice. Male mice maintained their caloric food intake while reducing their locomotor activity with either WD or HFD compared to LFD, whereas female mice increased their caloric food intake with WD feeding. Locomotor activity of female mice did not significantly change upon WD or HFD feeding, yet female mice exhibited increased energy expenditure compared to WD or HFD fed male mice. Glucose tolerance tests performed at 4, 12 and 20 weeks of dietary intervention revealed impaired glucose tolerance that was worse in male mice compared to females. Furthermore, male mice exhibited an increase in pancreatic β cell area as well as reduced insulin sensitivity after HFD feeding compared to WD or LFD, whereas female mice did not.

CONCLUSIONS: Male and female C57BL/6 J mice exhibited strikingly different responses in weight, food consumption, locomotor activity, energy expenditure and β cell adaptation upon dietary manipulation, with the latter exhibiting less striking phenotypic changes. We conclude that the nature of these responses emphasizes the need to contextualize studies of obesity pathophysiology and treatment with respect to sex.

Year of Publication
2021
Journal
Journal of diabetes and its complications
Volume
35
Issue
2
Number of Pages
107795
Date Published
02/2021
ISSN Number
1873-460X
DOI
10.1016/j.jdiacomp.2020.107795
Alternate Journal
J Diabetes Complications
PMID
33308894
PMCID
PMC7856196
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