posted on 2010-02-01, 00:00authored byJuan Molero Navajas, Scott Lee, I Leizerman, A Chajut, Adrian Cooper, Ken WalderKen Walder
Objective: To examine the effects of rosiglitazone in intramyocellular lipid (IMCL) content in diabetic Psammomys obesus using novel electron microscopy technologies.
Background: P. obesus is an unique polygenic model of obesity and type 2 diabetes. Male diabetic P. obesus were treated daily with 5 mg/Kg Rosiglitazone by oral gavage for 14 days. Data were compared with a group of age-matched diabetic P. obesus treated with saline vehicle.
Methods: Assessment of insulin resistance and adiposity were determine before and after the treatment period by oral glucose tolerance test (oGTT) and dual energy X-ray absorptiometry (DEXA) analysis. We used a new scanning electron microscopy technology, (WETSEM) to investigate the effects of rosiglitazone administration on IMCL content, size and distribution in red gastrocnemius muscle.
Results: Rosiglitazone treatment improved glucose tolerance in P. obesus with no difference in the overall body fat content although a significant reduction in subscapular fat mass was observed. Rosiglitazone changed the distribution of lipid droplet size in skeletal muscle. Treated animals tended to have smaller lipid droplets compared with saline-treated controls.
Conclusions: Since smaller IMCL droplets are associated with improvements in insulin sensitivity, we propose that this may be an important mechanism by which rosiglitazone affects glucose tolerance.