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Female Wistar Han ® Outbred Rats as a Model of Obesity When Fed High Fat Diets
Author(s) -
Flowers Jessica,
Horn Mandy Jayne
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.797.6
Subject(s) - medicine , endocrinology , leptin , obesity , adipose tissue , body weight , hormone , ovariectomized rat , chemistry
This study describes the development of a new rodent model of diet induced obesity utilizing non‐ovariectomized, virgin female Wistar Han ® rats. At 3 wk of age, rats were allowed ad libitum access to either high fat (HF‐1; 60% kcal from fat) or control (CON; 13% kcal from fat) diet for a period of 30 wk. A third cohort was started on the same high fat diet (HF‐2) at 8 wk of age for a period of 22 wk. Body weight was measured weekly. At 33 wk of age, food intake was recorded and body composition and energy expenditure were measured. Clinical chemistry parameters were assessed and plasma hormone levels were analyzed. At 33 weeks of age body weight was significantly greater ( P < 0.05) in HF compared to CON but not between HF groups (HF‐1, 335 g, HF‐2, 315 g, CON, 260 g). Percent body fat was also significantly greater in rats maintained on high fat compared to control diets but did not differ due to age at high fat diet initiation (HF‐1, 27%, HF‐2, 25%, CON, 13%). Leptin levels were significantly elevated in obese rats consistent with the increased proportion of body fat; all other clinical chemistry and hormone levels measured were within normal range for rats. Total energy intake during the monitoring period was approximately 11% higher in HF rats compared to CON (HF‐1, 47.4 ± 3.1, HF‐2, 45.1 ± 2.6, CON, 41.6 ± 2.8 total kcal). During the dark cycle, HF rats were approximately 20% less active than CON (HF‐1, 15,667 ± 607, HF‐2, 15,662 ± 1095, CON, 18,535 ± 1023 total beam breaks). In conclusion, these female rats became obese with increased energy intake and reduced activity in the absence of surgical or genetic modification, suggesting a potential model for further evaluation of the interplay between leptin and estrogen on energy regulating pathways. Additionally, the rats are non‐diabetic despite a significant degree of obesity. This diet‐induced obesity model may have utility for testing novel anti‐obesity compounds to assess how gender specific hormonal differences may influence weight loss/gain outcomes. Support or Funding Information This research was privately funded by Envigo.