Diabetes was confirmed after the injection of alloxan monohydrate (Sigma–Aldrich, Germany) by measuring the fasting blood glucose concentration. The rats with blood glucose level ≥200 mg/dl were considered to be diabetic and were used in the experiment. The treatment with astaxanthin was started 7 days after diabetes confirmation and continued for 30 days.
The animals were allocated randomly to four groups of six animals each:
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[Control group], group C: rats received as vehicle 0.9% NaCl (w/v) and served as negative controls.
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[Alloxan treated group], group D: rats received a subcutaneous dose of alloxan (120 mg/kg of body weight) and included in study as diabetic rats.
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[Alloxan and astaxanthin treated group], group D-As: diabetic rats received astaxanthin (20 mg kg/body weight) dissolved in olive oil with daily gavage. The rats received single-dose per day in the morning.
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[Olive oil treated group] group D-OO: diabetic rats received olive oil.