Eur J Clin Invest 2010; 40 (2): 164–171

Background  The aim was to examine whether the inhibition of selective cyclooxygenase (COX) 2 activation could suppress the development of inflammatory reaction in visceral and subcutaneous abdominal fats of high‐fat‐induced obese rats.

Materials and methods  The rats were fed separately regular diet (CONT), high‐fat diet ad libitum or energy‐restrictedly (HFr) for 12 weeks. Rats fed high‐fat diet ad libitum were further divided into those co‐treated with vehicle (HFa), a selective COX2 inhibitor‐celecoxib (HFa‐Cel) or nimesulide (HFa‐Nim). Oral glucose tolerance test (OGTT) was performed at the end of weeks 4, 8, 12. Another set of rats with similar grouping was divided into those with a 4‐, 8‐ or 12‐week intervention for tissue sampling.

Results  Body and epididymal fat weights were increased similarly in HFa, HFa‐Cel and HFa‐Nim. Time‐dependent increases in plasma insulin, triglyceride, impaired OGTT shown in HFa were significantly reversed in HFa‐Cel and HFa‐Nim. The obese‐linked increases in gene expressions of COX‐2, monocyte chemoattractant protein‐1 (MCP‐1) and tumour necrosis factor‐α (TNF‐α) in epididymal and subcutaneous fats (especially in the former) were significantly suppressed in HFa‐Cel and HFa‐Nim. The protein contents of MCP‐1 and TNF‐α in epididymal fats were changed consistently with their gene expressions. Plasma MCP‐1 was increased time‐dependently in HFa and suppressed in HFa‐Cel and HFa‐Nim. The increased CD68 positive cells showed in both epididymal and subcutaneous fats of HFa were significantly attenuated in HFa‐Cel and HFa‐Nim.

Conclusions  Our findings suggest that COX2 activation is crucially involved in the development of inflammatory response in adipose tissues of high‐fat‐induced obese rats.