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BioMed Research International
Volume 2015 (2015), Article ID 602313, 10 pages
http://dx.doi.org/10.1155/2015/602313
Research Article

N-Acetylneuraminic Acid Supplementation Prevents High Fat Diet-Induced Insulin Resistance in Rats through Transcriptional and Nontranscriptional Mechanisms

1Laboratory of Molecular Biomedicine, Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
2Cardiology Department, Affiliated Hospital of Chengde Medical University, Chengde, Hebei 067000, China
3Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
4Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
5Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia

Received 25 June 2015; Revised 29 October 2015; Accepted 4 November 2015

Academic Editor: Sheba Mohankumar

Copyright © 2015 Zhang Yida et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

N-Acetylneuraminic acid (Neu5Ac) is a biomarker of cardiometabolic diseases. In the present study, we tested the hypothesis that dietary Neu5Ac may improve cardiometabolic indices. A high fat diet (HFD) + Neu5Ac (50 or 400 mg/kg BW/day) was fed to rats and compared with HFD + simvastatin (10 mg/kg BW/day) or HFD alone for 12 weeks. Weights and serum biochemicals (lipid profile, oral glucose tolerance test, leptin, adiponectin, and insulin) were measured, and mRNA levels of insulin signaling genes were determined. The results indicated that low and high doses of sialic acid (SA) improved metabolic indices, although only the oral glucose tolerance test, serum triglycerides, leptin, and adiponectin were significantly better than those in the HFD and HFD + simvastatin groups (). Furthermore, the results showed that only high-dose SA significantly affected the transcription of hepatic and adipose tissue insulin signaling genes. The data suggested that SA prevented HFD-induced insulin resistance in rats after 12 weeks of administration through nontranscriptionally mediated biochemical changes that may have differentially sialylated glycoprotein structures at a low dose. At higher doses, SA induced transcriptional regulation of insulin signaling genes. These effects suggest that low and high doses of SA may produce similar metabolic outcomes in relation to insulin sensitivity through multiple mechanisms. These findings are worth studying further.