Visceral Fat Accumulation is Associated with Oxidative Stress and Increased Matrix Metalloproteinase-9 Expression in Atherogenic Factor-overlapped Model Rats
Visceral fat accumulation in lifestyle-related diseases increases the risk of atherosclerosis. Matrix metalloproteinases (MMPs) play an important role in the progression of atherosclerosis. We examined atherogenic factor-overlapped model rats to clarify the relationships among visceral fat, oxidative stress, and MMPs. We used four groups of male, 11-month-old, spontaneously hypertensive hyperlipidemic rats (SHHRs) or Sprague-Dawley (SD) rats. Animals were fed either a diet of high fat and 30% sucrose solution (HFDS) or a normal diet (ND) ad libitum for 6 months. The visceral fat weight increased by approximately three fold in SHHR-HFDS compared to SHHR-ND. The oxidative stress marker in plasma and MMP-9 mRNA expression in white blood cells increased in SHHR-HFDS compared to the other groups. A correlation was determined between oxidative stress and visceral fat or MMP-9 mRNA in all rats. Lipid deposition and immunostaining of CD68 and MMP-9 were observed mainly in the intima of aorta in SHHR-HFDS, while tissue inhibitor of metalloproteinase-1 mRNA expression decreased in both SHHR groups. The findings suggested that increased oxidative stress due to the visceral fat accumulation induced MMP-9 expression and macrophage accumulation in the intima of aorta in lifestyle-related disease model rats
