Basic—Alimentary TractGastric Bypass Increases Energy Expenditure in Rats
Section snippets
Animals and Housing
Thirty adult diet-induced obese male Wistar rats weighing 480–500 g were used for energy expenditure experiments, and 16 adult male Wistar rats weighing 330–350 g were used for morphometric gut analysis. All animals were individually housed under artificial 12-hour/12-hour light-dark cycle and at a room temperature of 21°C ± 2°C unless otherwise stated. Water and standard chow were available ad libitum. All experiments were performed under a license issued by the Home Office United Kingdom
Body Weight
Figure 2 shows the body weight changes for both groups. For the energy expenditure experiments (Figure 2A), body weight was significantly lower in gastric bypass rats compared with the sham-operated, ad libitum fed group from day 5 after surgery. On postoperative day 70, the difference in weight was almost 200 g (sham-operated, ad libitum fed: 603.2 ± 6.6 g vs bypass: 414.3 ± 13.8 g, P < .0001). After a short period of postsurgical weight loss, sham-operated, ad libitum fed rats fed constantly
Discussion
Our data in the rat gastric bypass model are consistent with previous findings that gastric bypass surgery is effective to reduce body weight and especially to maintain body weight loss.4, 9, 10, 12, 16 We confirmed that body weight loss after gastric bypass was associated with a significant loss of fat mass and to a lesser degree of nonadipose body mass.26, 27 Food intake was reduced in gastric bypass rats, which may be partly explained by hormonally mediated mechanisms.9, 16, 28 Importantly,
Acknowledgments
The authors thank Dr Jacquelien Hillebrand (ETH Zürich) and Manuela Munz for help in measurement of body composition and Winnie Ho for assistance with the histology.
K.A.S. is an Alberta Heritage Foundation for Medical Research Medical Scientist.
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Conflicts of interest The authors disclose no conflicts.
Funding Supported by the Deutsche Forschungsgemeinschaft (DFG; to M.B.); by the Swiss National Research Foundation (to T.L., C.L.); by a Department of Health Clinician scientist award (to S.B. and C.le R.); support from the NIHR Biomedical Research Centre funding scheme to Imperial College London; by the Markin Undergraduate Student Research Program (to M.W.); and from Canadian Institutes of Health Research (to K.A.S.).