Weight loss and brown adipose tissue reduction in rat model of sleep apnea.
BACKGROUND
Obesity is related to obstructive sleep apnea-hypopnea syndrome (OSAHS), but its roles in OSAHS as cause or consequence are not fully clarified. Isocapnic intermittent hypoxia (IIH) is a model of OSAHS. We verified the effect of IIH on body weight and brown adipose tissue (BAT) of Wistar rats.


METHODS
Nine-month-old male breeders Wistar rats of two groups were studied: 8 rats submitted to IIH and 5 control rats submitted to sham IIH. The rats were weighed at the baseline and at the end of three weeks, after being placed in the IIH apparatus seven days per week, eight hours a day, in the lights on period, simulating an apnea index of 30/hour. After experimental period, the animals were weighed and measured as well as the BAT, abdominal, perirenal, and epididymal fat, the heart, and the gastrocnemius muscle.


RESULTS
Body weight of the hypoxia group decreased 17 +/- 7 grams, significantly different from the variation observed in the control group (p = 0,001). The BAT was 15% lighter in the hypoxia group and reached marginally the alpha error probability (p = 0.054).


CONCLUSIONS
Our preliminary results justify a larger study for a longer time in order to confirm the effect of isocapnic intermittent hypoxia on body weight and BAT.
Martinez
Denis
D
Division of Cardiology, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil. dm@ufrgs.br
Vasconcellos
Luiz F T
LF
de Oliveira
Patricia G
PG
Konrad
Signorá P
SP
D002001:Adipose Tissue, Brown / Q000503:physiopathology*; D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D000860:Hypoxia / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*; D015431:Weight Loss / Q000502:physiology*