Studies have identified that serum-free hemoglobin subunits correlate positively with the severity of nonalcoholic fatty liver disease (NAFLD). However, the role of hemoglobin in the development of NAFLD remains unclear. In the present study, a rat model of NAFLD was developed, using a westernized diet high in saturated fat and refined sugar. Since a “westernized” diet is also high in red meat, we tested the effect of hemoglobin as a dietary source of heme in our model. Sprague-Dawley rats were fed ad libitum for 4 weeks either control diet (7% fat), westernized diet (WD, 18% fat + 1% cholesterol), hemoglobin diet (7% fat + 2.5% Hb), or westernized and hemoglobin diet (18% fat + 1% cholesterol + 2.5% Hb). Rats fed WD developed features of NAFLD, including insulin resistance and accumulation of liver fatty acids in the form of triglycerides, increased lipid peroxidation (F2-Isoprostanes), and liver fibrotic marker (hydroxyproline). Hemoglobin consumption significantly influenced several biomarkers of NAFLD and hepatic biochemistry, suggesting a possible interaction with diet and/or liver lipid pathways. The complex mechanisms of interaction between WD and hemoglobin in our rat model warrants further studies to examine the role of dietary heme on NAFLD. 1. Introduction Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as the most common cause of chronic liver disease in many industrialized and developing countries. It is estimated to affect approximately 30% and 10–20% of adults and children, respectively, in the USA and its prevalence is increasing in many countries where consumption of “western diets,” high in fat, is rising [1]. Recently, a prospective epidemiological study reported a significant incidence of NAFLD in nonobese and nonaffluent populations in India [2]. Interestingly, approximately 30% of NAFLD patients have hyperferritinemia [3] and serum hemoglobin subunits α and β increase with severity of the disease in NAFLD patients [4–6]. The prevailing concept of NAFLD is the “two hit” theory that centers on the initial accumulation of fatty acids (FAs) in the liver followed by a sequence of events associated with oxidative stress, lipid peroxidation, and inflammation, resulting in liver injury [7, 8]. However, the exact pathophysiological mechanisms are not fully understood. Therefore, reliable animal models of NAFLD are important to identify the relevant pathophysiology involved in the development of NAFLD in order to develop effective therapeutic strategy. Many groups have developed and studied experimental models for NAFLD
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