Histologic, Metabolic, and Inflammatory Changes in the Liver of High-fat Diet-induced Obese Rats before and after Vitamin D Administration

The current study aimed to investigate the effects of vitamin D administration on the markers of inflammation and metabolic damages in the liver of high-fat diet-induced obese rats. Forty male Wistar rats were divided into two groups of control receiving a normal diet (ND) and intervention receiving a high-fat diet (HFD). After 16 weeks, each group was divided into two groups including ND, ND + vitamin D, HFD, and HFD + vitamin D. Vitamin D was administered by oral gavage for five weeks at the dose of 500 IU/kg. Hepatic MCP-1, TGF-β, and NF-κB levels, serum liver enzymes, and serum lipids, and histological and structural changes in the liver were determined. Vitamin D administration significantly reduced the monocyte chemoattractant protein (MCP)-1 concentrations in the HFD + vitamin D group compared with the HFD group and reduced liver Transforming growth factor beta (TGF-β) levels in both vitamin D-treated groups (p<0.05). Moreover, a significant reduction in the serum levels of aspartate amino transferase (AST) and alanine amino transferase (ALT) in vitamin D treated groups was identified (p<0.05). A significant improvement in lipids and a pronounced improvement in the markers of liver histology damage including fat accumulation, aggregation of inflammatory cells, pre-apoptotic changes, hepatic sinusoidal dilatation, and necrotic pyknosis in the Kupffer cells were also identified. Our results demonstrated that vitamin D has potential effects in ameliorating the inflammatory, metabolic, and histologic changes in the liver of these animals.