Investigation of the effects of spirulina platensis on metabolic and behavioral parameters and cognitive function in early-onset HİGH-fat diet-induced obesity in rats

Obesity-induced metabolic changes can lead learning and memory impairment and behavioral disorders. Spirulina Platensis (SP) is a blue-green microalgae, which has antioxidant, antiinflamatory, neuroprotective, antidiabetic and antiobesity properties. Sirtuins are enzymes, which modulate various biologic functions as gene transcription, cell differentiation, energy metabolism, aging and apoptosis. This study was made to investigate the dose-dependent effects of SP on learning and memory, behavior parameters as depression, brain TNF-α and Sirtuin-1 levels in high fat-induced obesity. 4 weeks old Sprague Dawley male rats were divided into four groups; control, high fat diet (HFD), HFD+SP150 (150 mg/kg/day), HFD+SP450 (450 mg/kg/day). Rats except for the control group exposed to 60% high fat diet along 12 weeks. Last 6 weeks SP or vehicle administered by oral gavage. Learning and memory was assessed using the Morris water maze and behavioral performance was assessed using the T-maze, Open field test and forced swimming test. After the behavioral tests, rats were sacrificed and blood samples and brain regions were taken. Biochemical assessments and Elisa tests were made. HFD group gained more weight than control and HFD+SP450 groups (p<0.05). Leptin for HFD significantly higher than control in plasma. HFD for 12 weeks did not induced cognitive impairment in MWM test. The OFT and T-maze test showed no significant difference between groups in distance traveled. In FST, immobile time for HFD group significantly higher than control, HFD+SP150 and HFD+SP450 group (p<0.05). No significant difference was found between the groups in Sirtuin-1 levels in the brain regions. TNF-α for HFD+SP450 was lower than control in prefrontal cortex. No significant difference was found amygdala and hippocampus. The result of our study shows chronic high fat diet and SP treatment does not affect learning and memory function. Spirulina treatment positively affects chronic high fat-induced depressive behavior without affecting Sirtuin-1 levels. Key words: behaviour, high fat diet, obesity, sirtuin-1, spirulina