EFFECT OF ANTIOXIDANT TREATMENT ON SOME INDICATORS OF OBESITY-INDUCED CHANGES IN INSULIN SENSITIVITY AND BETA-CELL FUNCTION IN NEW ZEALAND WHITE RABBITs

摘要

The current study was conducted to investigate the impact of dietary antioxidant supplementation on obesity-induced changes in some surrogate indices of insulin sensitivity and Я-cell function in New Zealand white rabbits. Three groups of rabbits were used in this experiment: castrated animals treated with antioxidants (vitamin E and d-limonene, Immunoprotect) (Cim; n=6), castrated obese animals (CO; n=6) and non-castrated non-obese controls (NC; n=7). At the end of the follow-up period of 2 months after castration an intravenous glucose tolerance test (IVGTT) was performed after 12-hour fasting. Blood samples for determination of simplified estimates of insulin resistance and β-cell function were obtained at baseline and at various time intervals over the 120-min test. In addition, lipid content in m. Longissimus lumborum и m. Semimembranosus was determined. Some of the simplified measurements of insulin resistance (fasting insulin, fasting insulin to glucose ratio,НОМAins.resist index), beta-cell function (HOMAβ-cell, AUCinsulin0→60 min) and muscles lipid content in CO were higher while QUICKI and Bennett indices were lower than in controls. No differences in surrogate indices between CIm and NC groups were found suggesting improvement of insulin sensitivity and β-cell function after antioxidant supplementation. Surrogate indices are simple and reliable indicators of insulin sensitivity and β-cell function in rabbits as they were closely associated with markers of obesity and can be modified by antioxidant supplementation.