Influence of Term of Exposure to High-Fat Diet-Induced Obesity on Myocardial Collagen Type I and III

BACKGROUND: Obesity is a risk factor for many medical complications; medical research has shown that hemodynamic, morphological and functional abnormalities are correlated with the duration and severity of obesity. OBJECTIVE: Present study determined the influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III. METHODS: Thirty-day-old male Wistar rats were randomly distributed into two groups: a control (C) group fed a standard rat chow and an obese (Ob) group alternately fed one of four palatable high-fat diets. Each diet was changed daily, and the rats were maintained on their respective diets for 15 (C(15) and Ob(15)) and 30 (C(30) and Ob(30)) consecutive weeks. Obesity was determined by adiposity index. RESULTS: The Ob(15) group was similar to the C(15) group regarding the expression of myocardial collagen type I; however, expression in the Ob(30) group was less than C(30) group. The time of exposure to obesity was associated with a reduction in collagen type I in Ob(30) when compared with Ob(15). Obesity did not affect collagen type III expression. CONCLUSION: This study showed that the time of exposure to obesity for 30 weeks induced by unsaturated high-fat diet caused a reduction in myocardial collagen type I expression in the obese rats. However, no effect was seen on myocardial collagen type III expression.