Objective: To investigate the effect of viral inoculation by adenovirus 5 (Ad5) on body composition in a mouse model.
Design: Longitudinal monitoring before and after a single injection of virus or saline.
Subjects: Two groups of CD1 mice, one group given a single intraperitoneal dose of Ad5 and the control group, saline.
Measurements: Bodyweights and food intake were recorded before and up to 21 weeks after inoculation. At the end of the study, whole-body 1H magnetic resonance spectroscopy (MRS) and localised in vivo 1H MRS spectroscopy of the liver was performed to assess whole-body adiposity and intrahepatic lipid content, respectively.
Results: Ad5-treated animals gained significantly more weight over a period of 21 weeks after inoculation than the controls, 21.8 g (18.8-25.0) and 18.8 g (17.3-19.8) respectively, (P<0.05). The gain in bodyweight in the former animals arises from increased deposition of adipose tissue as measured by whole-body 1H MRS. Adiposity was 6.7% (3.10-11.20%), and 2.40% (0.85-5.65%) for the Ad5-treated and control animals, respectively (P<0.05). No significant difference in intrahepatic lipid content or food intake was observed between the two groups.
Conclusion: The significantly higher percentage of adipose tissue in the Ad5-treated mice suggest viral infection may play a contributory role to a predisposition to obesity, although its contribution relative to other factors remains to be determined.