Involvement of sex, strain and age factors in high fat diet-induced obesity in C57BL6J and BALB/cA mice

Although a number of obesity animal models have been reported, each model possesses different characteristics of obesity, suggesting care should be taken in choosing an animal model suitable for the experimental purpose. In this report, we fed 4-(young) and 52-week-old (middle-aged) C57BL/6J (B6) and young BALB/cA (BALB/c) mice with a high fat diet (HFD) for 9 weeks, and investigated the clinical and histological characteristics of obesity. In BALB/c mice, males gained more body weight and body fat weight and had higher energy intake than females by HFD feeding. Comparing the effect of HFD feeding between the strains of mice, BALB/c male mice accumulated more hepatic lipid than B6 male mice. In addition, middle-aged B6 mice increased the ratio of fat to body weight and hepatic lipid accumulation more than young mice. In conclusion, the characteristics of obesity induced by HFD feeding were influenced by the sex, strain and age of mice. Sex steroid hormones, hepatic lipid metabolism and systemic metabolism might be involved in these factors. The basic data in this study will be useful for the development of animal models of high fat diet-induced obesity.