Dietary intake of Spirulina platensis alters HSP70 gene expression profiles in the brain of rats in an experimental model of mixed stress.

Spirulina platensis has gradually gained more attention for its therapeutic, antioxidant, and anti-inflammatory potential worldwide. However, the current molecular knowledge about the effects of spirulina on stress-related genes is rather limited. The effects of dietary intake of spirulina on the HSP70 gene expression were assessed in a controlled in vivo experimental design. Moreover, alterations in serum corticosterone levels, IL-2, IL-4, IFN-Υ, triglyceride, ALT, AST, relative gene expression values, and the correlations between them were evaluated. A total of 36 rats were divided into four groups: control group, stress-only group, spirulina group, and spirulina+stress group. To control the dose administration, S. platensis was applied by a gastric gavage in stress groups. Crowded environment stress and hosting alone stress were applied to the stress-only group and spirulina + stress group. RNA was extracted from brain samples using TRIpure and the relative gene expression assessment was performed using Roche-LightCycler-480-II real-time PCR-System. Gene expression values were remarkably different among the four experimental groups. The differences between stress-only and the spirulina groups were statistically significant (P<0.05). The correlation between the HSP70 gene expression and the IFN-Υ was found to be statistically significant (P<0.05; r=0.50). Results indicate a novel effect of spirulina on the HSP70 expression related to the stress-response. Data presented in this study may be useful for further studies to define not only the molecular genetic aspects through dietary S. platensis but also the effects of spirulina on stress-response and animal welfare.

The Preventive Role of Spirulina Platensis (Arthrospira Platensis) in Immune and Oxidative Insults in a Stress-induced Rat Model.

INTRODUCTION: There is a balance between oxidative stress, antioxidant capacity and immune response. Their roles in physiological and behavioural mechanisms are important for the maintenance of the organism's internal equilibrium. This study aimed to evaluate the antioxidant effects of the exogenous alga Spirulina platensis (Arthrospira platensis) in a stress-induced rat model, and to describe its possible mechanism of action. MATERIAL AND METHODS: Thirty-six adult male Sprague Dawley rats were separated into four groups: control (C), stress (S), S. platensis (Sp), and S. platensis + stress (SpS). The rats in groups Sp and SpS were fed with 1,500 mg/kg b.w./day Spirulina platensis for 28 days. All rats were exposed to prolonged light phase conditions (18 h light : 6 h dark) for 14 days. The SpS and S groups were exposed to stress by being kept isolated and in a crowded environment. Blood samples were obtained by puncturing the heart on the 28th day. The effect of stress on serum corticosterone, oxidative stress markers (TOS, TAC, PON1, OSI) and immunological parameters (IL-2, IL-4, IFN-É£) were tested. Also, the brain, heart, intestines (duodenum, ileum, and colon), kidney, liver, spleen, and stomach of the rats were weighed. RESULTS: Serum corticosterone levels were higher in the S group than in the C group, and significantly lower in the SpS group than in the S group. Mean total antioxidant capacity were lower in the S group than in the C group, and Spirulina reversed this change. Although not significantly different, IL-2 was lower in the S group than in the C group. However, in the SpS group, IL-2 increased due to Spirulina platensis mitigating effects of stress. CONCLUSION: Male rats fed a diet with Spirulina platensis could experience significantly milder physiological changes during stress, although stress patterns may be different. Exogenous antioxidant supplements merit further investigation in animals and humans where the endogenous defence mechanism against stress may not be sufficient.