Effects of Long-Term Supplementation of Blue-Green Algae on Lipid Metabolism in C57BL/6J mice.

Ji-Young Lee

doi:10.15226/jnhfs.2014.00108

Abstract

Dyslipidemia is a primary risk factor for cardiovascular disease. In this study, we investigated the effect of long-term supplementation of two blue-green algae (BGA) species, i.e., Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), on lipid metabolism in vivo. Male C57BL/6J mice were fed an AIN-93G/M diet supplemented with 2.5 or 5% (wt/wt) NO or SP for 6 months. Mice fed NO and SP showed lower plasma total cholesterol (TC) and triglyceride (TG) concentrations than control at certain months during 6 month experimental period. Both BGA supplementation for 6 months significantly increased hepatic TC contents whereas SP-fed groups had significantly less TG levels in the liver compared with control and NO groups. None of BGA-fed animals showed significantly different mRNA levels of sterol regulatory element binding protein 2, while 3-hydroxy-3-methylglutaryl coenzyme A reductase and low-density lipoprotein receptor (LDLR) expression was higher in NO groups than the other groups in the liver. Furthermore, NO supplementation increased the hepatic expression of acetyl-CoA carboxylase 1, stearoyl CoA desaturase 1, carnitine palmitoyltransferase 1α, and acyl-CoA oxidase 1 but SP did not elicit any significant changes in mRNA levels of the genes compared with control. LDLR protein level was significantly higher in NO 2.5% and SP 5%, as compared to the control and NO 5% groups; while the level of fatty acid synthase protein in the liver was significantly higher in NO 5% and SP 5%, than that in the control group. In conclusion, our results suggest that long-term supplementation of NO and SP decreased plasma TC and TG concentrations. Therefore, supplementation of NO and SP may be potentially beneficial for preventing dyslipidemia-associated chronic diseases.

Highlights

Cardiovascular disease (CVD) is the leading cause of death in the developed countries [1]
Nostoc commune var. sphaeroides Kützing (NO), another Blue-green algae (BGA) species has been used in indigenous countries to treat inflammation, night blindness, indigestion, and chronic fatigue [15,16,17]
We demonstrated that lipid extract from NO inhibited the maturation of sterol regulatory element binding protein 1c (SREBP-1c) and Sterol Regulatory Element Binding Protein (SREBP)-2, repressing the expression of lipogenic genes and cholesterol biosynthetic and uptake genes, respectively, in HepG2 cells [20]

Summary

Introduction

Cardiovascular disease (CVD) is the leading cause of death in the developed countries [1]. Studies have shown hypolipidemic and anti-inflammatory effects of several BGA species [12]. In both mice and humans, Spirulina plantensis (SP) has been shown to lower plasma total cholesterol (TC) and LDL cholesterol (LDL-C), and triglyceride (TG) concentrations [13,14]. Sphaeroides Kützing (NO), another BGA species has been used in indigenous countries to treat inflammation, night blindness, indigestion, and chronic fatigue [15,16,17]. In male Wistar rats that were fed a high cholesterol diet, 5% NO supplementation elicited a hypolipidemic effect [18]. Our previous study found that male C57BL/6J mice fed a 5% NO-supplemented diet for 4 weeks showed significantly lower plasma TC and TG levels [19]. We demonstrated that lipid extract from NO inhibited the maturation of sterol regulatory element binding protein 1c (SREBP-1c) and SREBP-2, repressing the expression of lipogenic genes and cholesterol biosynthetic and uptake genes, respectively, in HepG2 cells [20]

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Conclusion