Investigating the effect of zeaxanthin on olanzapine-induced metabolic disorders in rats.

Objective: Olanzapine (OLZ) is used by some patients with bipolar disorder and schizophrenia. Some of its side effects include weight gain and metabolic syndrome. Zeaxanthin (Zx), a yellow pigment found in egg yolk as well as some yellow and orange plants and fruits, is an anti-obesity factor that aids in the treatment of metabolic disorders. The effects of Zx on metabolic disorders caused by OLZ were investigated in this study.

Materials and methods: Female Wistar rats were randomly divided into seven groups (n=6): 1. control (vehicle); 2. OLZ (5 mg/kg, 14 days, intraperitoneal (i.p.)); 3-5. OLZ + Zx (12.5, 25, and 50 mg/kg, 14 days, gavage); 6. OLZ+ metformin (100 mg/kg, 14 days, i.p.); and 7. Zx (50 mg/kg, 14 days). Weight changes were checked every 3 days and food intake was monitored every day. Systolic blood pressure, insulin, blood sugar, triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and leptin levels were evaluated on the last day of the study.

Results: OLZ caused an increase in weight (84.5% increase on day 15), food intake, blood pressure, triglyceride, LDL, insulin, blood sugar, and leptin compared to the control group (p<0.01 and p<0.001). The use of different doses of Zx (12.5, 25, and 50 mg/kg) and metformin decreased weight (the percentages of weigh reduction on day 15 were 91.92% for Zx (50 mg/kg) and 59.39% for metformin), food intake, systolic blood pressure, triglyceride, LDL, insulin, blood sugar, and leptin compared to the OLZ group. The amounts of cholesterol and HDL were not different in different groups.

Conclusion: Zx alleviates metabolic abnormalities including hypertension, hyperglycemia, and dyslipidemia in rats.