Summary
The effect of rofecoxib (Vioxx), a cyclooxygenase (COX)-2 inhibitor, on adipose tissue
development was studied in a murine model of diet-induced obesity. Oral administration
of Vioxx for six weeks (34 mg/kg/day) to C57Bl/6 mice kept on high-fat diet (n = 19)
resulted in a significant reduction in total body weight (p < 0.01) and of subcutaneous
(p < 0.05) and gonadal (p< 0.01) adipose tissue mass, as compared to placebo-treated
animals (n = 21).There was no significant difference in food intake between both groups
(2.8 ± 0.09 vs.3.0 ± 0.10 g/day;p = 0.20).Administration ofVioxx resulted in reduced
total cholesterol and high-density lipoprotein (HDL) cholesterol levels (p < 0.0001)
and in enhanced levels of liver enzymes, as compared to placebo. In the gonadal but
not in the subcutaneous adipose tissue, adipocytes were smaller after Vioxx treatment
(p < 0.05).The macrophage content was significantly lower in gonadal adipose tissues
of Vioxx-treated mice (p < 0.05), but not in the subcutaneous adipose tissues. This
was, however, not associated with differences in adipose tissue levels of the pro-inflammatory
tumor necrosis factor (TNF)-α. Blood vessel size or density in either fat pad were
not affected by Vioxx treatment. Thus, in a nutritionally induced murine obesity model,
oral administration of Vioxx, as compared to placebo, resulted in reduced adipose
tissue development, associated with lower feeding efficiency and smaller adipocytes.
Keywords
Obesity - adipose tissue - cyclooxygenase - rofecoxib