[Induction of experimental type 2 diabetes using olive and rump oils in rat]

ABSTRACT

Too much fat in the diet can cause insulin resistance. This study was conducted to provide a suitable experimental model of type 2 diabetes and to compare the potency of olive and rump oils in the induction of insulin resistance. The study was done in three phases, each with 15 male Sprague dawley rats. The control, olive oil, and rump oil, groups were fed the commercial diet, and diets supplemented by 31% olive or rump oils for three weeks, respectively [first stage], and then diabetes was induced by IP injection of 35 mg/kg STZ [stages 2 and 3]. The oral glucose tolerance test [OGTT] showed glucose intolerance in both oil groups, compared to the control group [p<0.05], in stage 1, but increases in blood glucose levels were higher in the olive oil group in the second stage. TC and LDL-C levels increased by both the oils, especially olive oil. Insulin level was higher in the rump oil groups, especially after diabetes induction. Insulin sensitivity, as shown by the insulin tolerance test [ITT] and HOMA-IR, were decreased by both oils, especially rump oil. Although both oils had significant effects on metabolism, olive oil use was accompanied by more dyslipidemia, whereas rump oil increased insulin resistance more effectively. It seems that rump oil may be a more appropriate model for studies investigating disorders of carbohydrate metabolism of type 2 diabetes and olive oil, for induction of dyslipidemia and probably the metabolic syndrome