Microalgal Macular Pigment Alleviated the Pathogenic Process in the Streptozotocin-induced Diabetic ApoE-deficient Mice

Abstract

Type 2 diabetes mellitus (T2DM) is one of the fastest growing epidemics in human history and characteristic is insulin resistance (IR), and endocrine disorder that promoted to decline in insulin production and inhibit cellular effects. Patients with T2DM would lead to many complications such as diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, diabetic foot, atherosclerosis, vascular inflammation, and hepatogenous diabetes due to hyperglycemia. Even after using medical treatment and lifestyle modifications, it is still hard to achieve the goal of reducing blood glucose to an optimal level. Microalga Chlorella sp., a unicellular green alga that has been used as a health food and nutritional product in the last few decades. Macular pigment (MP) produced by Chlorella sp. consists of rich lutein and zeaxanthin, which are regarded as the antioxidants to hyperglycemia-induced oxidative stress. MP is widely used in eye health care, however, few studies focused on scientifically exploring the protection mechanism of MP on diabetes mellitus. Therefore, this study aimed to explore MP extracted from Chlorella on reducing retinopathy and atherosclerosis damages in the diabetic apolipoprotein E deficient mice (ApoE−/−) with high-fat diet feeding and streptozotocin treatment. The results show that MP supplement could significantly reduce glucose tolerance, IR, inflammatory cytokines TNF-α and IL-6 levels, and the serum level of disease markers, i.e., triglyceride (TG), total cholesterol (TCHO), glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), total protein (TP), albumin (ALB), and blood urea nitrogen (BUN) in the diabetic ApoE−/− mice. In addition, the expression levels of cellular antioxidant enzymes were significantly increased and the adhesion factors as well as MAPK pathway proteins in renal tissues were significantly reduced after MP supplementation. The pathological changes of pancreatic islet morphology, hepatic lipid accumulation, outer nuclear layer and aortic plaque of the diabetic ApoE−/− mice were significantly alleviated by MP supplement. At present, most MP products are derived from marigold, Calendula offcinalis, in the market. However, microalgae cultivation includes the advantages on no seasonal limit, no competition, high yield and carbon reduction compared with other plants. In summary, the microalgal MP improved IR, ameliorated atherosclerosis, and alleviated retinopathy in the diabetic ApoE−/− mice. Consequently, the microalgal MP is potentially to be a healthy food ingredient for the biological effcacy of scavenging free radicals and stabilizing blood glucose. This work was supported by the grants of NSTC 110-2312-B-A49-001-MY3, NSTC 112-2811-B-A49 -501, NSTC 112-2811-B-A49 -503, NSTC 112-2321-B-A49 -018 and NSTC 112-2321-B-A49-005, from the National Science and Technology Council (NSTC), Taiwan. This work was also financially supported by the “Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B)” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project of the National Yang Ming Chiao Tung University and Ministry of Education (MOE), Taiwan. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.